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Germline pathogenic variants in BRCA1/BRCA2 are associated with ovarian cancer, fallopian tube cancer, primary peritoneal cancer, male breast cancer, prostate cancer, pancreatic cancer, and early-onset breast cancer. BRCA1/BRCA2-associated cancer risks are inherited in an autosomal dominant manner.
Prevalence ofBRCA1/2Pathogenic Variants
Several studies have assessed the frequency of BRCA1 or BRCA2 pathogenic variants in women with breast or ovarian cancers.[
Among the general population, the likelihood of having any BRCA pathogenic variant is as follows:
BRCA1/2 pathogenic variants are not currently associated with genetic anticipation, despite suggestive findings from a few studies.[
BRCA1/2founder pathogenic variants
The same pathogenic variant can be found in multiple unrelated families due to the founder effect (a pathogenic variant identified in a contemporary population that can be traced to a small group of founders isolated by geographic, cultural, or other factors). The presence of these founder pathogenic variants have practical implications for genetic testing.
Founder pathogenic variants have been observed in multiple population groups. In individuals with AJ ancestry, two specific BRCA1 pathogenic variants (185delAG and 5382insC) and one BRCA2 pathogenic variant (6174delT) are common. However, nonfounder BRCA pathogenic variants have also been reported at a rate of 3% to 15% in the AJ population.[
Among AJ individuals, the likelihood of having a BRCA pathogenic variant is as follows:
Some laboratories offer testing for ethnic-specific variants (particularly the three AJ founder variants). However, searching only for the AJ founder variants increases the risk of receiving a false-negative genetic test result (i.e., missing a nonfounder BRCA1/2 pathogenic variant or a pathogenic variant in another cancer susceptibility gene).[
Founder pathogenic variants have been observed in other non-AJ racial and ethnic groups, such as groups of Icelandic, Hispanic, West African, French Canadian, Polish, Sephardic Jewish, and Bahamian descent.[
BRCA1/2de novo pathogenic variant rate
The spontaneous pathogenic variant rate (de novo pathogenic variant rate) in the BRCA genes is thought to be 5% or less, based on data from limited studies.[
Detection ofBRCA1/2Variants
Variant-screening methods have differing sensitivities. Large genomic alterations such as translocations, inversions, deletions, or insertions are missed by most variant-screening techniques, including direct DNA sequencing. However, testing for these alterations is commercially available. Such rearrangements may be responsible for 12% to 18% of BRCA1 inactivating variants but are seen less frequently in the BRCA2 gene and in individuals of AJ descent.[
Indications forBRCA1/2Genetic Testing
Several professional organizations and expert panels, including the American Society of Clinical Oncology,[
Related Conditions
Fanconi anemia, a rare inherited condition, may be associated with biallelic pathogenic variants in some breast cancer susceptibility genes, including BRCA2. For more information, see the Fanconi anemia genes section in Genetics of Breast and Gynecologic Cancers.
References:
The proportion of individuals who carry a hereditary cancer syndrome pathogenic variant and develop cancer is called penetrance. (Refer to the Penetrance of Inherited Susceptibility to Hereditary Breast and/or Gynecologic Cancers section of Genetics of Breast and Gynecologic Cancers for more information.) While numerous studies have estimated cancer risks in carriers of BRCA1 and BRCA2 pathogenic variants, making precise penetrance estimates in an individual carrier is difficult.
Cancer Sites[ |
BRCA1 | BRCA2 | ||
---|---|---|---|---|
a For more information on the association betweenBRCA1/BRCA2and prostate cancer, see the BRCA1 and BRCA2section in Genetics of Prostate Cancer. | ||||
+++ Multiple studies demonstrated association and are relatively consistent. | ||||
++ Multiple studies and the predominance of the evidence are positive. | ||||
+ May be an association, predominantly single studies; smaller limited studies and/or inconsistent but weighted toward positive. | ||||
Strength of Evidence | Lifetime Risk | Strength of Evidence | Lifetime Risk | |
Breast (female) | +++ | 55% to 65% | +++ | 45% to 47% |
Ovary, fallopian tube, peritoneum | +++ | 39% | +++ | 11% to 17% |
Breast (male) | + | 1% to 2% | +++ | 5% to 10% |
Pancreas | ++ | Lower thanBRCA2 | +++ | 3% to 5% |
Prostatea | + | Undefined | +++ | 27% |
The risk to develop both breast and ovarian cancers is consistently higher in BRCA1 pathogenic variant carriers than in BRCA2 pathogenic variant carriers.[
Study | Breast Cancer Risk (95% CI) | Ovarian Cancer Risk (95% CI) | ||
---|---|---|---|---|
CI = confidence interval. | ||||
a Risk estimate calculated up to age 70 years. | ||||
b Risk estimate calculated up to age 80 years. | ||||
BRCA1 | BRCA2 | BRCA1 | BRCA2 | |
Antoniou et al. (2003)[ |
65% (44–78)a | 45% (31–56)a | 39% (18–54)a | 11% (2.4–19)a |
Chen et al. (2007)[ |
55% (50–59)a | 47% (42–51)a | 39% (34–45)a | 17% (13–21)a |
Kuchenbaecker et al. (2017)[ |
72% (65–79)b | 69% (61–77)b | 44% (36–53)b | 17% (11–25)b |
Female Breast Cancer Risks
First primary breast cancer risks
The estimated cumulative risks of breast cancer by age 70 years in two meta-analyses were 55% to 65% for carriers of BRCA1 pathogenic variants and 45% to 47% for carriers of BRCA2 pathogenic variants.[
Contralateral breast cancer (CBC) risk
Most studies that assess second primary breast cancer risk use CBCs, since it can be challenging to determine if ipsilateral breast cancers are recurrences or second primary breast cancers.
As early as 1995, the Breast Cancer Linkage Consortium estimated the risk of CBC in BRCA1 carriers to be as high as 60% by age 60 years.[
Several factors can increase CBC risk. These factors may help explain the variability of CBC rates observed in BRCA1/BRCA2 carriers:
The following treatment options may have an impact on CBC risk in BRCA1/BRCA2 carriers:
Women who are planning their initial surgery for breast cancer treatment weigh the risks and benefits of risk-reducing bilateral mastectomy. During this process, factors that contribute to CBC risk may help optimize decision making when they are combined in a multifactorial risk model.
Breast cancer risks after ovarian cancer diagnosis
Key points:
Studies have explored the risk of primary breast cancer after BRCA-related ovarian cancer. In one study, 164 BRCA1/BRCA2 carriers with primary epithelial ovarian, fallopian tube, or primary peritoneal cancers were followed for subsequent events.[
BRCA1/2-associated breast cancer pathology
Key point:
Overall evidence suggests DCIS is part of the BRCA1/BRCA2 cancer spectrum, particularly in BRCA2 carriers. However, the prevalence of BRCA1/2 pathogenic variants in DCIS patients, unselected for family history, is less than 5%.[
There is growing evidence that preinvasive lesions are a component of the BRCA phenotype. The Breast Cancer Linkage Consortium initially reported a relative lack of an in situ component in BRCA1-associated breast cancers.[
BRCA1-associated breast cancer pathology
Key point:
Several studies evaluating pathological patterns seen in BRCA1-associated breast cancers have suggested an association with adverse pathological and biological features. These findings include higher than expected frequencies of medullary histology, high histological grades, areas of necrosis, trabecular growth patterns, aneuploidy, high S-phase fractions, high mitotic indexes, and frequent TP53 variants.[
There is considerable, but not complete, overlap between the triple-negative and basal-like subtype cancers, both of which are common in BRCA1-associated breast cancers,[
The prevalence of germline BRCA1 pathogenic variants in women with triple-negative breast cancer (TNBC) is significant, both in women undergoing clinical genetic testing (and thus, selected in large part for family history) and in unselected triple-negative patients, with pathogenic variants reported in 9% to 35%.[
It has been hypothesized that many BRCA1 tumors are derived from the basal epithelial layer of cells of the normal mammary gland, which account for 3% to 15% of unselected invasive ductal cancers. If the basal epithelial cells of the breast represent the breast stem cells, the regulatory role suggested for wild-type BRCA1 may partly explain the aggressive phenotype of BRCA1-associated breast cancer when BRCA1 function is damaged.[
The most accurate method for identifying basal-like breast cancers is through gene expression studies, which have been used to classify breast cancers into biologically and clinically meaningful groups.[
BRCA2-associated breast cancer pathology
Key point:
The phenotype for BRCA2-related tumors appears to be more heterogeneous and is less well-characterized than that of BRCA1, although they are generally ER- and PR-positive.[
Ovarian, Fallopian Tube, and Primary Peritoneal Cancer Risks
Key points:
The estimated cumulative risks of ovarian cancer by age 70 years in two meta-analyses were 39% for carriers of BRCA1 pathogenic variants and 11% to 17% for carriers of BRCA2 pathogenic variants.[
BRCA pathogenic variants also confer an increased risk of fallopian tube and primary peritoneal carcinomas. One large study from a familial registry of carriers of BRCA1 pathogenic variants has found a 120-fold RR of fallopian tube cancer among carriers of BRCA1 pathogenic variants compared with the general population.[
Pathologies ofBRCA1/2-associated ovarian, fallopian tube, and primary peritoneal cancers
Key points:
Ovarian cancers in women with BRCA1 and BRCA2 pathogenic variants are more likely to be high-grade serous adenocarcinomas and are less likely to be mucinous or borderline tumors.[
Histopathological examinations of fallopian tubes removed from women with a hereditary predisposition to ovarian cancer show dysplastic and hyperplastic lesions that are suggestive of a premalignant phenotype.[
High-grade serous ovarian carcinomas have a higher incidence of somatic TP53 variants.[
Unlike high-grade serous carcinomas, low-grade serous ovarian cancers are less likely to be part of the BRCA1/BRCA2 spectrum.[
Uterine Cancer Risk
Key point:
Some reports have suggested an increased incidence of uterine carcinoma in BRCA1/2 pathogenic variant carriers,[
Male Breast Cancer Risk
Men with BRCA2 pathogenic variants, and to a lesser extent BRCA1 pathogenic variants, have an increased risk to develop breast cancer, with lifetime risks ranging from 5% to 10% and 1% to 2%, respectively.[
Prostate Cancer Risk
Key points:
Men carrying BRCA2 pathogenic variants, and to a lesser extent BRCA1 pathogenic variants, have an approximately threefold to sevenfold increased risk of developing prostate cancer.[
Pancreatic Cancer Risk
Key point:
Studies of familial pancreatic cancer (FPC) [
Melanoma Risk
Melanoma is another cancer that is associated with BRCA2 pathogenic variants in some, but not all, studies.[
Other Cancer Risks
Taken together, there are insufficient data to support an increased risk of colorectal cancer (CRC) in BRCA1 and BRCA2 carriers. Therefore, at this time, carriers of BRCA1 pathogenic variants should adhere to population-screening recommendations for CRC.[
There is mounting evidence supporting an association between BRCA1/BRCA2 pathogenic variants and increased gastric cancer risk. Multigene panel testing of over 80 genes (hereditary cancer syndrome genes, including hereditary gastric cancer) in 34 patients with gastric cancer demonstrated that six patients had a pathogenic variant (17.6%), half of which were pathogenic variants in BRCA1/BRCA2.[
Risk Modifiers
The observed variation in penetrance has led to the hypothesis that other genetic and/or environmental factors modify cancer risk in carriers of BRCA1/2 pathogenic variants. There is a growing body of literature identifying genetic and nongenetic factors that contribute to the observed variation in cancer rates seen in families with BRCA1/BRCA2 pathogenic variants.
Genetic modifiers
The largest studies investigating genetic modifiers of breast and ovarian cancer risk to date have come from the CIMBA, a large international effort with genotypic and phenotypic data on more than 15,000 BRCA1 and 10,000 BRCA2 carriers.[
Lifestyle factors, reproductive factors, and other modifiers of cancer risks
For more information about risk factors that may increase cancer risks in BRCA1/2 carriers, see the following sections in the Genetics of Breast and Gynecologic Cancers summary:
Genotype-Phenotype Correlations
Some genotype -phenotype correlations have been identified in both BRCA1 and BRCA2 pathogenic variant families. None of the studies have had sufficient numbers of pathogenic variant–positive individuals to make definitive conclusions, and the findings are probably not sufficiently established to use in individual risk assessment and management. Studies have identified ovarian cancer cluster regions and breast cancer cluster regions in BRCA1 and BRCA2.[
In an Australian study of 122 families with a pathogenic variant in BRCA1, large genomic rearrangement variants were associated with higher-risk features in breast and ovarian cancers, including younger age at breast cancer diagnosis and higher incidence of bilateral breast cancers.[
Studies of penetrance for carriers of specific individual variants are not usually large enough to provide stable estimates, but numerous studies of the AJ founder pathogenic variants have been conducted. One group of researchers analyzed the subset of families with one of the AJ founder pathogenic variants from its larger meta-analyses and found that the estimated penetrance for the individual pathogenic variants was very similar to the corresponding estimates among all carriers.[
Another study from the CIMBA group looked at the phenotype of women with breast cancer who had inherited pathogenic variants in both BRCA1 and BRCA2.[
References:
Increasing data are available on the outcomes of interventions to reduce risk in people with a genetic susceptibility to breast cancer or ovarian cancer.[
Breast Cancer Screening, Surveillance, and Risk-Reduction Strategies forBRCA1/2Carriers
Screening and surveillance for breast cancer
Refer to the PDQ summary on Breast Cancer Screening for information on screening in the general population.
Breast self-examination
In the general population, evidence for the value of breast self-examination (BSE) is limited.
Little direct prospective evidence exists regarding BSE in individuals with an increased risk of breast cancer.[
Level of evidence: 5
Clinical breast examination (CBE)
Few prospective data exist regarding the utility of CBE in detection of early breast cancer.[
Level of evidence: 5
Mammography
In the general population, strong evidence suggests that regular mammography screening of women aged 50 to 59 years leads to a 25% to 30% reduction in breast cancer mortality. (Refer to the PDQ summary on Breast Cancer Screening for more information.)
Certain observations raise concerns that carriers of BRCA pathogenic variants may be more prone to radiation-induced breast cancer than women without pathogenic variants. The BRCA1 and BRCA2 proteins are important in cellular mechanisms of DNA damage repair, including those involved in repairing radiation-induced damage. Some studies have suggested intermediate radiation sensitivity in cells that are heterozygous for a BRCA variant, but this is not consistent and varies by experimental system and end point.
Three studies have failed to find convincing evidence of an association between ionizing radiation exposure and increased breast cancer risk in BRCA1 and BRCA2 pathogenic variant carriers.[
With the routine use of magnetic resonance imaging (MRI) in carriers of BRCA1 and BRCA2 pathogenic variants, any potential benefit of mammographic screening must be carefully weighed against potential risks, particularly in young women.[
Level of evidence: 2
Magnetic resonance imaging
Because of the relative insensitivity of mammography alone in women with inherited breast cancer risk, a number of screening modalities have been investigated in high-risk women, including in BRCA1/2 carriers. Many studies, including relatively large multi-institutional trials, have described breast MRI screening in women at elevated risk for breast cancer.[
Despite some limitations, these studies consistently demonstrate that breast MRI is more sensitive than mammography or ultrasound at detecting breast cancer in high-risk women.[
However, breast MRI may have reduced specificity when compared with other breast cancer screening methods.[
A systematic review has also shown that breast MRI is better at detecting breast cancer than mammography alone in young women with high breast cancer risk. However, mammogram may detect some lesions (i.e., DCIS) that are not easily identified by MRI.[
Despite the apparent sensitivity of MRI screening, some women screened with MRI will develop life-threatening breast cancer. In a prospective study of 51 carriers of BRCA1 pathogenic variants and 41 carriers of BRCA2 pathogenic variants screened with annual mammograms and MRIs, 11 breast cancers (9 invasive and 2 DCIS) were detected. Six cancers were first detected on MRI, three were first detected by mammogram, and two were interval cancers. All breast cancers occurred in carriers of BRCA1 pathogenic variants, suggesting a continued high risk of BRCA1-related breast cancer after oophorectomy in the short term. These results suggest that surveillance and prevention strategies may have differing outcomes in carriers of BRCA1 and BRCA2 pathogenic variants.[
It is unclear whether mammography and MRI should be done simultaneously or in an alternating fashion (each test is done annually but screening occurs every 6 months). One study has suggested that the most cost-effective screening strategy in carriers of BRCA1 and BRCA2 pathogenic variants may be annual MRI beginning at age 25 years, with alternating MRI and digital mammography beginning at age 30 years.[
Evidence does not support the use of routine MRI after risk-reducing mastectomy (RRM). A retrospective review of 159 women (including 58 BRCA1/2 carriers) who underwent RRM reported a low yield of breast cancers detected by annual MRI screening over an 8-year period. MRI was negative in 98% of patients and was associated with a false-positive rate of 90%.[
In summary, evidence strongly supports the integral role of breast MRI in breast cancer surveillance for carriers of BRCA1/BRCA2 pathogenic variants.
Level of evidence: 3
Ultrasound
Several studies have reported instances of breast cancer detected by ultrasound that were missed by mammography, as discussed in one review.[
Level of evidence: 3
Breast cancer screening in individuals diagnosed with ovarian cancer
Mathematical modeling suggests that for women with BRCA-associated ovarian cancers, breast cancer screening should consist of mammography and CBE. The consideration of MRI and/or risk-reducing mastectomy may be beneficial for women with early-stage ovarian cancers or for long-term ovarian cancer survivors.[
Risk-reducing strategies for breast cancer
Risk-reducing mastectomy (RRM) for unaffected females
Because there are no randomized, prospective trials of RRM versus observation, data are limited to cohort and case-control studies. The available data demonstrate that RRM does decrease breast cancer incidence in high-risk patients,[
The Prevention and Observation of Surgical Endpoints study group also estimated the degree of breast cancer risk reduction after RRM in carriers of BRCA1/BRCA2 pathogenic variants. The rate of breast cancer in 105 carriers of pathogenic variants who underwent bilateral RRM was compared with that of 378 carriers who did not choose surgery. Bilateral mastectomy reduced the risk of breast cancer by approximately 90% after a mean follow-up period of 6.4 years.[
A computer-simulated survival analysis using a Monte Carlo model included breast MRI, mammography, RRM, and risk-reducing salpingo-oophorectomy (RRSO) and examined the impact of each intervention separately on carriers of BRCA1 and BRCA2 pathogenic variants.[
Level of evidence: 3ai
RRM for affected females
If RRM is effective at lowering breast cancer risk in unaffected women, what is its role in women with unilateral breast cancer? This question often arises in discussions about surgical options with women who have unilateral breast cancer and hereditary risks. This section addresses the role of contralateral risk-reducing mastectomy (CRRM) in women being treated with mastectomy. When the appropriateness of CRRM is being assessed for women with unilateral breast cancer, the first task is to determine the risk of contralateral breast cancer (CBC).
In carriers of BRCA pathogenic variants with a diagnosis of breast cancer, the risk of a second, unrelated breast cancer is related to age at initial diagnosis, biology, and systemic therapies used, but is clearly higher than that in the general population (approximately 0.3% per year in the general population).[
A retrospective study of 593 carriers of BRCA1 and BRCA2 pathogenic variants included 105 women with unilateral breast cancer who underwent CRRM and had a 10-year survival rate of 89%, compared with 71% in the group that did not undergo contralateral risk-reducing surgery (P < .001).[
A Dutch cohort of 583 patients identified between 1980 and 2011, who had both a BRCA pathogenic variant and a diagnosis of unilateral breast cancer, were evaluated for the effect of CRRM.[
A retrospective study of 390 women with early-stage breast cancer who were from families with a known BRCA1/BRCA2 pathogenic variant found a significant improvement in survival for women who underwent RRM when compared with those who chose unilateral mastectomy.[
All of these studies are limited by the biases introduced in relatively small, retrospective studies among very select populations. There is often limited data on potential confounding variables such as socioeconomic status, comorbidities, and access to care. It has been suggested that women who elect to undergo RRM are healthier by virtue of being able to tolerate more extensive surgery. This theory is supported by one study that used Surveillance, Epidemiology, and End Results (SEER) Program data to examine the association between CRRM and outcomes among women with unilateral breast cancer stages I through III. Results showed a reduction in all-cause mortality and breast cancer–specific mortality, and also in noncancer event mortality, a finding that would not be expected to be related to CRRM.[
Level of evidence: 3ai
Nipple-sparing mastectomy
The option of nipple-sparing mastectomy (NSM) in carriers of BRCA pathogenic variants undergoing risk-reducing procedures has been controversial because of concerns about increased breast tissue left behind at surgery to keep the nipple-areolar complex (NAC) viable. The ability to leave behind minimal residual tissue, however, may be related to experience and technique. In a retrospective review of NSM performed in carriers of BRCA pathogenic variants at two hospitals between 2007 and 2014, NSM was performed on 397 breasts in 201 carriers of BRCA pathogenic variants.[
Level of evidence: 3aii
Incidence of breast cancer or other lesions in RRM
The predominant histopathological findings at the time of RRM in unaffected women with pathogenic BRCA variants are proliferative lesions that do not require additional treatment. Studies describing histopathological findings in RRM specimens from women with BRCA1 or BRCA2 pathogenic variants have been somewhat inconsistent. In two series, proliferative lesions associated with an increased risk of breast cancer (lobular carcinoma in situ, atypical lobular hyperplasia, atypical ductal hyperplasia, and DCIS) were noted in 37% to 46% of women with pathogenic variants who underwent either unilateral or bilateral RRM.[
Risk-reducing salpingo-oophorectomy (RRSO) for breast cancer risk reduction
In the general population, removal of both ovaries has been associated with a reduction in breast cancer risk of up to 75%, depending on parity, weight, and age at time of artificial menopause. (Refer to the PDQ summary on Breast Cancer Prevention for more information.) A Mayo Clinic study of 680 women at various levels of familial risk found that in women younger than 60 years who had bilateral oophorectomy, the likelihood of breast cancers developing was reduced for all risk groups.[
Evidence regarding the effect of RRSO on breast cancer risk has evolved. Early small studies suggested RRSO provided a protective benefit against developing breast cancer. A meta-analysis of RRSO and breast and ovarian/fallopian tube cancers in carriers of BRCA1/BRCA2 pathogenic variants reported that RRSO was associated with a significant reduction in breast cancer risk (overall: HR, 0.49; 95% CI, 0.37–0.65; BRCA1: HR, 0.47; 95% CI, 0.35–0.64; BRCA2: HR, 0.47; 95% CI, 0.26–0.84).[
A prospective, multicenter, cohort study of 2,482 carriers of BRCA1/BRCA2 pathogenic variants reported an association between RRSO and a reduction in all-cause mortality (HR, 0.40; 95% CI, 0.26–0.61), breast cancer–specific mortality (HR, 0.44; 95% CI, 0.26–0.76), and ovarian cancer–specific mortality (HR, 0.21; 95% CI, 0.06–0.80).[
For more information, see the Hormone Replacement Therapy in Carriers of BRCA1/2 Pathogenic Variants section.
Level of evidence: 3ai
Chemopreventive agents for reducing breast cancer risk
Tamoxifen (a synthetic antiestrogen) increases breast-cell growth inhibitory factors and concomitantly reduces breast-cell growth stimulatory factors. The National Surgical Adjuvant Breast and Bowel Project Breast Cancer Prevention Trial (NSABP-P-1), a prospective, randomized, double-blind trial, compared tamoxifen (20 mg/day) with placebo for 5 years in high-risk women (defined by a Gail model risk score >1.66, age >60 y, or lobular carcinoma in situ). Tamoxifen was shown to reduce the risk of invasive breast cancer by 49%. The protective effect was largely confined to ER-positive breast cancer, which was reduced by 69%. The incidence of ER-negative cancer was not significantly reduced.[
Subsequently, the International Breast Cancer Intervention Study 1 (IBIS-1) breast cancer prevention trial randomly assigned 7,154 women between the ages of 35 and 70 years to receive tamoxifen or placebo for 5 years. Eligibility for the trial was based on family history or abnormal benign breast disease. At a median follow-up of 16 years, there was a 29% reduction in risk of breast cancer in the tamoxifen arm (HR, 0.71; 95% CI, 0.60–0.83). There was a 43% reduction in risk for invasive ER-positive breast cancer (HR, 0.66; 95% CI, 0.54–0.81) and a 35% reduction in risk for DCIS (HR, 0.65; 95% CI 0.43–1.00). There was no reduction in risk of invasive ER-negative breast cancer.[
Level of evidence (tamoxifen in a high-risk population): 1aii
A substudy of the NSABP-P-1 trial evaluated the effectiveness of tamoxifen in preventing breast cancer in carriers of BRCA1/BRCA2 pathogenic variants older than 35 years. BRCA2-positive women benefited from tamoxifen to the same extent as BRCA1/BRCA2 pathogenic variant–negative participants; however, tamoxifen use among healthy women with BRCA1 pathogenic variants did not appear to reduce breast cancer incidence. These data must be viewed with caution because of the small number of carriers of pathogenic variants in the sample (8 BRCA1 carriers and 11 BRCA2 carriers).[
Level of evidence: 1aii
In contrast to the very limited data on primary prevention in carriers of BRCA1 and BRCA2 pathogenic variants with tamoxifen, several studies have found a protective effect of tamoxifen on the risk of CBC.[
The STAR trial (NSABP-P-2) included more than 19,000 women and compared 5 years of raloxifene versus tamoxifen in reducing the risk of invasive breast cancer.[
Another case-control study of carriers of pathogenic variants and noncarriers identified through ascertainment of women with bilateral breast cancer found that systemic adjuvant chemotherapy reduced CBC risk among carriers of pathogenic variants (RR, 0.5; 95% CI, 0.2–1.0). Tamoxifen was associated with a nonsignificant risk reduction (RR, 0.7; 95% CI, 0.3–1.8). Similar risk reduction was seen in noncarriers. However, given the higher absolute CBC risk in carriers, there is potentially a greater impact of adjuvant treatment in risk reduction.[
The effect of tamoxifen on ovarian cancer risk was studied in 714 carriers of BRCA1 pathogenic variants. All subjects had a prior histories of breast cancer. Use of tamoxifen was not associated with an increased risk of subsequent ovarian cancers (odds ratio [OR], 0.78; 95% CI, 0.46–1.33).[
Ovarian Cancer Screening, Surveillance, and Risk-Reduction Strategies forBRCA1/2Carriers
Risk-reducing strategies for ovarian cancer
Risk-reducing salpingo-oophorectomy for ovarian cancer risk reduction
RRSO in BRCA1/2 carriers is an effective strategy to reduce the risk of ovarian and tubal cancers. Numerous studies have found that women with an inherited risk of breast and ovarian cancer have a decreased risk of ovarian cancer after RRSO. (Refer to the RRSO for breast cancer risk reduction section for more information on RRSO's effect on breast cancer risk.) A prospective, single-institution study of 170 women with BRCA1 or BRCA2 pathogenic variants showed the HR was 0.15 (95% CI, 0.02–1.31) for ovarian, fallopian tube, or primary peritoneal cancers. The HR was 0.32 (95% CI, 0.08–1.2) for breast cancers after bilateral salpingo-oophorectomy.[
In addition to a reduction in risk of ovarian and breast cancer, RRSO may also significantly improve OS and breast and ovarian cancer–specific survival. A prospective cohort study of 666 women with germline pathogenic variants in BRCA1 and BRCA2 found an HR for overall mortality of 0.24 (95% CI, 0.08–0.71) in women who had RRSO compared with women who did not.[
Level of evidence: 2aii
Occult cancers and premalignant lesions found during RRSO
Studies on the associations between RRSO and cancer risk reduction have begun to clarify the spectrum of occult cancers that can be discovered at the time of surgery. Primary fallopian tube cancers, primary peritoneal cancers, and occult ovarian cancers have all been reported. Several case series have reported on the prevalence of malignant findings in pathogenic variant carriers undergoing risk-reducing oophorectomies. In studies with 50 or more subjects, prevalence of malignant findings ranged from 1.2% to 11%.[
In addition to occult cancers, premalignant lesions have also been described in fallopian tube tissue removed during RRSO. These pathological findings were consistent with the identification of germline BRCA1 and BRCA2 pathogenic variants in women affected with both fallopian tube and primary peritoneal cancers.[
Evidence shows that RRSO best practices include routine collection of peritoneal washings and careful adherence to comprehensive pathological evaluation of the entire adnexa with the use of serial sectioning.[
The peritoneum appears to remain at low risk for Müllerian-type adenocarcinoma, even after RRSO.[
Outcomes of occult lesions after RRSO
There are limited data regarding outcomes of BRCA1 and BRCA2 carriers with occult lesions found during RRSO. In a multi-institution study of 32 women with invasive carcinomas (n = 15) or serous tubal intraepithelial carcinomas (STIC) (n = 17), 47% of women with invasive cancer had a recurrence at a median time of 32.5 months after RRSO, with an OS rate of 73%.[
Another study confirmed the malignant potential of STIC lesions. While 3 of 243 women (1.2%) with benign pathology found during RRSO subsequently developed primary peritoneal carcinomas, 2 of 9 women (22%) with STIC lesions developed high-grade, serous pelvic carcinomas after a median follow-up time of 63 months.[
Timing of RRSO
Given current ovarian cancer screening limitations and the high risk of disease associated with BRCA1 and BRCA2 pathogenic variants, NCCN guidelines recommend RRSO as an effective risk-reducing option. Ovarian cancer onset typically occurs 8 to 10 years later in patients with a BRCA2 pathogenic variant than in patients with a BRCA1 pathogenic variant. Hence, NCCN states that it is reasonable to postpone RRSO until age 40 to 45 years in most patients with a BRCA2 pathogenic variant. However, RRSO may be performed at a younger age if individuals with a BRCA2 pathogenic variant have a family member who had ovarian cancer at a young age.[
Concomitant hysterectomy at time of RRSO
The role of concomitant hysterectomy at the time of RRSO in BRCA1/BRCA2 carriers is controversial. Some reports have suggested an increased incidence of uterine carcinoma in BRCA1/BRCA2 carriers,[
Studies have shown that removing the uterus is not necessary to reduce cancer risk. BRCA1/BRCA2 pathogenic variant prevalence was not increased in 200 Ashkenazi Jewish women with endometrial carcinomas or in 56 unselected women with uterine papillary serous carcinomas.[
Morbidity, mortality, and quality of life (QOL) considerations after RRSO
For more information, see the Psychosocial outcomes associated with RRSO section in Genetics of Breast and Gynecologic Cancers.
For women who are premenopausal at the time of RRSO, the symptoms of surgical menopause (e.g., hot flashes, mood swings, weight gain, and genitourinary complaints) can cause a significant impairment in their QOL. To reduce the impact of these symptoms, providers often prescribe a time-limited course of systemic HRT after surgery. In one longitudinal cohort, 61% of patients (mean age, 42 y) reported using HRT after having RRSO.[
Studies have examined the effect of RRSO on QOL. One study examined 846 high-risk women, of whom 44% underwent RRSO and 56% participated in periodic screening.[
The long-term nononcologic effects of RRSO in BRCA1/BRCA2 carriers are unknown. In the general population, RRSO has been associated with increased risks of cardiovascular disease, dementia, death from lung cancer, and overall mortality.[
Chemopreventive agents for reducing ovarian cancer risk
Oral contraceptives (OCs) have been shown to have a protective effect against ovarian cancer in the general population.[
There has been great interest in determining whether a similar benefit extends to women who are at increased genetic risk of ovarian cancer. A multicenter study of 799 ovarian cancer patients with BRCA1 or BRCA2 pathogenic variants, and 2,424 control patients without ovarian cancer but with a BRCA1 or BRCA2 pathogenic variant, showed a significant reduction in ovarian cancer risk with use of OCs (OR, 0.56; 95% CI, 0.45–0.71). Compared with never-use of OCs, duration up to 1 year was associated with an OR of 0.67 (95% CI, 0.50–0.89). The OR for each year of OC use was 0.95 (95% CI, 0.92–0.97), with a maximum observed protection at 3 years to 5 years of use.[
Level of evidence: 3aii
Risk-reducing bilateral salpingectomy
Risk-reducing bilateral salpingectomy with delayed oophorectomy has been suggested as an interim procedure to reduce risk in BRCA1/BRCA2 carriers.[
In a statistical Markov model using Monte Carlo simulation, risk-reducing salpingectomy with delayed oophorectomy was a cost-effective strategy considering quality-adjusted life expectancy for women with pathogenic variants in BRCA1/BRCA2.[
Prospective studies are under way evaluating the impact of bilateral salpingectomy with delayed oophorectomy on patient satisfaction and the reduction in ovarian cancer.[
Level of evidence: 4b
Screening and surveillance
Effective ovarian cancer screening is particularly important for women carrying pathogenic variants in BRCA1, BRCA2, and mismatch repair genes (e.g., MLH1, MSH2, MSH6, PMS2) because these pathogenic variants increase ovarian cancer risk.
While this is an active area of research with a number of promising new biomarkers in early development, at present, none of these biomarkers alone or in combination have been sufficiently well studied to justify their routine clinical use for screening purposes, either in the general population or in women at increased genetic risk.
Refer to the PDQ summary on Ovarian, Fallopian Tube, and Primary Peritoneal Cancers Screening for information on screening in the general population.
Clinical examination
In the general population, clinical examination of the ovaries has neither the specificity nor the sensitivity to reliably identify early-stage ovarian cancer. No data exist regarding the benefit of clinical examination of the ovaries (bimanual pelvic examination) in women at inherited risk of ovarian cancer.
Level of evidence: Insufficient evidence
Transvaginal ultrasound (TVUS)
The first prospective study of TVUS and cancer antigen–125 (CA-125) with survival as the primary outcome was completed in 2009. Of the 3,532 high-risk women screened, 981 were carriers of BRCA pathogenic variants, 49 of whom developed ovarian cancer. The 5- and 10-year survival rates were 58.6% (95% CI, 50.9%–66.3%) and 36% (95% CI, 27%–45%), respectively, and there were no differences in survival rates between carriers and noncarriers. A major limitation of the study was the absence of a control group. Despite limitations, this study suggests that annual surveillance by TVUS and CA-125 level appears to be ineffective in detecting tumors at an early stage to substantially influence survival.[
In the United Kingdom Familial Ovarian Cancer Screening Study, 3,563 women with an estimated 10% or higher lifetime risk of ovarian cancer were screened with annual ultrasound and serum CA-125 measurements for a mean of 3.2 years. Four of 13 screen-detected cancers were stage I or II. Women screened within the previous year were less likely to have higher than stage IIIC disease; there was also a trend towards better rates of optimal cytoreduction and improved OS. Furthermore, most of the cancers occurred in women with known ovarian cancer susceptibility genes, identifying a cohort at highest cancer risk for consideration of screening.[
Level of evidence: 4
Serum CA-125
A novel modification of CA-125 screening is based on the hypothesis that rising CA-125 levels over time may provide better ovarian cancer screening performance characteristics than simply classifying CA-125 as normal or abnormal based on an arbitrary cut-off value. This has been implemented in the form of the risk of ovarian cancer algorithm (ROCA), an investigational statistical model that incorporates serial CA-125 test results and other covariates into a computation that produces an estimate of the likelihood that ovarian cancer is present in the screened subject. The first report of this strategy, based on reanalysis of 5,550 average-risk women from the Stockholm Ovarian Cancer screening trial, suggested that ovarian cancer cases and controls could be distinguished with 99.7% sensitivity, 83% specificity, and a PPV of 16%. That PPV represents an eightfold increase over the 2% PPV reported with a single measure of CA-125.[
Two prospective trials in England used the ROCA. The United Kingdom Collaborative Trial of Ovarian Cancer Screening (UKCTOCS) randomly assigned normal-risk women to either (1) no screening, (2) annual ultrasound, or (3) multimodal screening (N = 202,638; accrual completed; follow-up ended in 2014), and the U.K. Familial Ovarian Cancer Screening Study (UKFOCSS) targeted high-risk women (accrual completed). There are also two high-risk cohorts using the ROCA under evaluation in the United States: the Cancer Genetics Network ROCA Study (N = 2,500; follow-up complete; analysis under way) and the Gynecologic Oncology Group Protocol 199 (GOG-0199; enrollment complete; follow-up ended in 2011).[
Level of evidence: 4
HRT in Carriers ofBRCA1/2Pathogenic Variants
The effect of HRT on breast cancer risk among carriers of a BRCA1 or BRCA2 pathogenic variant has been examined in two studies. In a prospective study of 462 carriers of BRCA1 and BRCA2 pathogenic variants, bilateral RRSO (n = 155) was significantly associated with breast cancer risk-reduction overall (HR, 0.40; 95% CI, 0.18–0.92). When carriers of pathogenic variants without bilateral RRSO or HRT were used as the comparison group, HRT use (n = 93) did not significantly alter the reduction in breast cancer risk associated with bilateral RRSO (HR, 0.37; 95% CI, 0.14–0.96).[
Level of evidence: 3aii
Male Breast Cancer Screening and Surveillance forBRCA1/2Carriers
Male breast cancer patients have historically presented with advanced-stage disease, which was thought to occur due to a lack of screening. While data on breast cancer screening (via mammogram) in men with inherited risk is limited, recent studies have suggested that the detection rate for male breast cancer is similar to or better than detection rates for breast cancer in women at population risk.[
NCCN guidelines recommend that men with a BRCA pathogenic variant learn how to perform BSEs at age 35 years.[
Prostate Cancer Screening and Surveillance forBRCA1/2Carriers
For more information, see the Screening in carriers of BRCA pathogenic variants section in Genetics of Prostate Cancer.
Management Guidelines forBRCA1/2Carriers
Table 3 lists several organizations that have published recommendations for cancer risk assessment and genetic counseling, genetic testing, and/or management for hereditary breast and ovarian cancers.
Organization | Referral Recommendations | Risk Assessment and Genetic Counseling Recommendations | Genetic Testing Recommendations | Management Recommendations |
---|---|---|---|---|
ACMG/NSGC = American College of Medical Genetics and Genomics/National Society of Genetic Counselors; ACOG = American College of Obstetricians and Gynecologists; ASCO = American Society of Clinical Oncology; ESMO = European Society for Medical Oncology; NAPBC = National Accreditation Program for Breast Centers; NCCN = National Comprehensive Cancer Network; NSGC = National Society of Genetic Counselors; SGO = Society of Gynecologic Oncology; USPSTF = U.S. Preventive Services Task Force. | ||||
a The USPSTF guidelines apply to individuals without a prior cancer diagnosis. | ||||
ACMG/NSGC (2015 and 2019)[ |
Addressed | Risk Assessment: Addressed | Not addressed | Not addressed |
Genetic Counseling: Addressed | ||||
ACOG (2017)[ |
Addressed | Risk Assessment: Addressed | Addressed | Addressed |
Genetic Counseling: Addressed | ||||
ASCO (2015)[ |
Not addressed | Risk Assessment: General recommendations; not specific to HBOC | General recommendations; not specific to HBOC | Not addressed |
Genetic Counseling: Addressed | ||||
ESMO (2023)[ |
Refers to other published guidelines | Risk Assessment: Refers to other published guidelines | Addressed | Addressed |
Genetic Counseling: Addressed | ||||
NSGC (2021)[ |
Addressed | Risk Assessment: Addressed | Addressed | Refers to other published guidelines |
Genetic Counseling: Addressed | ||||
NCCN (2024)[ |
Addressed | Risk Assessment: Addressed | Addressed | Addressed |
Genetic Counseling: Addressed | ||||
SGO (2015, 2017)[ |
Addressed | Risk Assessment: Addressed | Addressed | Addressed |
Genetic Counseling: Addressed | ||||
USPSTFa(2019)[ |
Addressed | Risk Assessment: Addressed | Addressed in general terms and other guidelines referenced | Addressed in general terms and other guidelines referenced |
Genetic Counseling: Addressed |
References:
Breast Cancer Treatment Strategies
Unique clinical and molecular features ofBRCA1/2-associated breast cancers
BRCA1-associated breast cancers are more likely to be subtyped as triple negative (TNBC), (e.g., lacking hormone receptors [HRs] or human epidermal growth factor receptor 2 [HER2] receptors). BRCA2-associated breast cancers are more likely to be HR-positive, although TNBCs are overrepresented when compared with sporadic breast cancers.[
In translational studies of primary breast cancers, genes with the highest frequencies of somatic alterations in BRCA1/2-mutated breast cancers include TP53 and PIK3CA.[
Biomarkers relevant in cancer care, such as measures of homologous recombination deficiency (HRD) or tumor mutational burden, appear to be consistent across trajectory of BRCA1/2-associated breast cancers, although datasets are currently limited.[
Systemic therapy forBRCA1/2-related breast cancer
Chemotherapy
BRCA1/2-related breast cancers are currently treated with standard chemotherapy agents. Newer agents, such as lurbinectedin, are under investigation.[
An active question is the use of platinum chemotherapy for TNBCs in both the neoadjuvant and metastatic settings.
Multiple studies in the early-stage breast cancer setting have not shown a clear benefit of cisplatin for germline BRCA1/2 carriers.
In the metastatic breast cancer setting, the Triple Negative Breast Cancer Trial (TNT trial) compared carboplatin with docetaxel in 43 subjects with BRCA1/2 germline pathogenic variants. These patients had greater responses to carboplatin than to docetaxel (objective response rate [ORR], 68% in 17 of 25 carboplatin-treated subjects vs. 33.3% in 6 of 18 docetaxel-treated subjects; absolute difference, 34.7%; P = .03). The progression-free survival (PFS) was 6.8 months in participants who received carboplatin and 4.4 months in participants who received docetaxel (interaction test: P = .002). Overall survival (OS) values did not differ between the two groups.[
While the efficacy of platinum therapy is under investigation in this patient population, patients with BRCA1/2-associated breast cancers are more likely to receive platinum therapy from oncologists, per Surveillance, Epidemiology, and End Results (SEER) Program data.[
Chemotherapeutic toxicities are not known to be increased in BRCA1/2 carriers.[
Level of evidence: 1
Targeted therapy: PARP inhibitors for breast cancer
PARP inhibitors have demonstrated an OS benefit for patients with BRCA-related breast cancers in the adjuvant setting and a PFS benefit (but not OS) in the metastatic setting.[
Olaparib is approved by the U.S. Food and Drug Administration (FDA) for the adjuvant treatment of patients with high-risk TNBCs/HR-positive breast cancers and a germline BRCA1/2 pathogenic variant. This approval is based on the OlympiA trial: a randomized, placebo-controlled, phase III study of 1,836 patients with high-risk TNBCs/HR-positive breast cancers who completed neoadjuvant/adjuvant chemotherapy, surgery, and radiation therapies.[
The FDA approved olaparib and talazoparib for the treatment of BRCA1/2-associated metastatic breast cancer. These approvals were granted based on the OlympiAD and EMBRACA trials:
Veliparib demonstrated promising early results in this patient population in the phase III BROCADE3 study.[
Numerous clinical trials involving patients with both early and metastatic breast cancers are studying the use of PARP inhibitors in combination with other DNA damage repair agents, immunotherapies, and other targeted therapies to improve responses, as well as to broaden the patient population who may benefit.[
An active question is the risk of myelodysplastic syndrome (MDS)/acute leukemia associated with PARP inhibitor therapy. In a safety meta-analysis of randomized controlled trials using PARP inhibitor therapy (including the OlympiAD and EMBRACA trials), 5% of the treatment-related MDS/leukemia cases occurred in patients with breast cancer.[
For more information about PARP inhibitor use in BRCA carriers with ovarian cancer, see the Systemic therapy with PARP inhibitors for ovarian cancer section.
Level of evidence: 1
Other targeted therapy
BRCA1/2-associated breast cancers are currently treated with standard targeted therapy agents.
Early studies suggest that patients who have germline BRCA1- and BRCA2-associated breast cancers may not respond as well to first-line cyclin-dependent kinase (CDK) 4/6 inhibitors that are given to individuals with metastatic breast cancers.[
Immunotherapy
BRCA1/2-associated breast cancers are currently treated with immunotherapy, in accordance with the standard of care. However, it is unknown how best to integrate existing FDA approvals for immunotherapy in patients with TNBC who take PARP inhibitors and have germline BRCA1/2-associated breast cancers.[
Several small combination trials have been conducted in individuals with breast cancer. Although some patients respond to a combination of a PARP inhibitor and immunotherapy, conclusions regarding benefit are limited by nonrandomized designs and different PARP inhibitors/immunotherapy agents.[
The use of immunotherapy in patients with BRCA1/2 pathogenic variants and in combination with PARP inhibitors remains a major area of active research.[
Level of evidence: 2
Breast conservation and radiation therapy inBRCA1/2carriers
While lumpectomy plus radiation therapy has become standard local-regional therapy for women with early-stage breast cancer, its use in women with a hereditary predisposition for breast cancer who do not choose immediate bilateral mastectomy is more complicated. Initial concerns about the potential for therapeutic radiation to induce tumors or cause excess toxicity in carriers of BRCA1/BRCA2 pathogenic variants were unfounded.[
Because of the established increased risk of second primary breast cancers, which may be up to 60% in younger women with BRCA1 pathogenic variants,[
Level of evidence: 3a
Ovarian Cancer Treatment Strategies
The molecular mechanisms that explain the improved prognosis in hereditary BRCA-associated ovarian cancers are unknown but may be related to the function of BRCA genes. BRCA genes play an important role in cell-cycle checkpoint activation and in the repair of damaged DNA via homologous recombination.[
Deficiencies in homologous repair can impair the cells' ability to repair DNA cross-links that result from certain chemotherapy agents, such as cisplatin. Preclinical data has demonstrated BRCA1 impacts chemosensitivity in breast cancer and ovarian cancer cell lines. Reduced BRCA1 protein expression has been shown to enhance cisplatin chemosensitivity.[
PARP pathway inhibitors have been studied for the treatment of BRCA1- or BRCA2-deficient ovarian cancers. (Refer to the Systemic therapy with PARP inhibitors for ovarian cancer section for more information about PARP inhibitors.) While PARP is involved in the repair of single-stranded breaks by base excision repair, BRCA1 and BRCA2 are active in the repair of double-stranded DNA breaks by homologous recombination. Therefore, it was hypothesized that inhibiting base excision repair with PARP inhibition in BRCA1- or BRCA2-deficient tumors leads to enhanced cell death, as two separate repair mechanisms would be compromised—the concept of synthetic lethality. The same concept may apply to tumors with HRD, and consequently, PARP inhibitors may have expanded use in women whose tumors have any homologous recombination defects beyond pathogenic variants in BRCA genes. In clinical practice, there are different tumor assays available to determine HRD tumors, which vary by method and definition. More study of PARP inhibitors in HRD ovarian cancers is ongoing.
Systemic therapy with PARP inhibitors for ovarian cancer
Olaparib
Studies have used PARP inhibitors in ovarian cancer after platinum-based chemotherapy. A phase I study of olaparib, an oral PARP inhibitor, demonstrated tolerability and activity in carriers of BRCA1 and BRCA2 pathogenic variants with ovarian, breast, and prostate cancers.[
Several phase II treatment studies have explored the efficacy of olaparib in patients with recurrent ovarian cancer, in both platinum-sensitive and platinum-resistant disease. Olaparib at 400 mg twice daily was used in a single-arm study to treat a spectrum of 298 BRCA-associated cancers, including breast, pancreas, prostate, and ovarian. Of the 193 women with ovarian cancer treated with olaparib, 31% had a response, and 40.4% had stable disease that persisted for at least 8 weeks.[
In contrast, other studies found that BRCA status did not predict survival advantage in women with platinum-sensitive ovarian cancer treated with olaparib. A randomized open-label trial assigned 90 women with recurrent platinum-sensitive ovarian cancer to either olaparib or cediranib and olaparib. Median PFS was significantly longer with the combination (17.7 mo vs. 9 mo) (HR, 0.42; 95% CI, 0.23–0.76). Subset analysis showed that combination cediranib and olaparib resulted in significantly longer PFS in the 43 BRCA wild-type/unknown patients than did single agent olaparib (16.5 mo vs. 5.7 mo) (HR, 0.32; P = .008) and a smaller trend toward increased PFS in 47 women with BRCA pathogenic variants (19.4 mo vs. 16.5 mo) (HR, 0.55; P = .16).[
In another study, women with BRCA1/BRCA2 pathogenic variants and recurrent ovarian cancer within 12 months of a prior platinum-based regimen were randomly assigned to receive doxorubicin hydrochloride liposome (Doxil) (n = 33) versus olaparib at 200 mg twice daily (n = 32) versus olaparib at 400 mg twice daily (n = 32). This study did not show a difference in PFS between the groups, which was the primary endpoint.[
As maintenance treatment, olaparib has shown significantly improved PFS in platinum-sensitive recurrent ovarian cancer. In a randomized controlled study of 265 patients (Study 19), those who received olaparib had a PFS of 8.4 months compared with 4.8 months in those who received the placebo (HR, 0.35; 95% CI, 0.25–0.49).[
Olaparib has demonstrated significant benefit as maintenance treatment in women with newly diagnosed advanced-stage, BRCA-associated ovarian cancer following response to primary treatment. The SOLO-1 trial randomly assigned 391 women with BRCA pathogenic variants to receive either olaparib 300 mg twice daily (n = 260) or placebo (n = 131) for 2 years after their primary surgeries and platinum-based chemotherapy. After a median follow-up of 41 months, women receiving olaparib had a 70% lower risk of disease progression or death compared with women receiving placebo with an estimated improved PFS of approximately 3 years.[
Rucaparib
Rucaparib is a small molecule inhibitor of PARP-1, -2, and -3 and was approved in the United States for the treatment of advanced germline BRCA1/BRCA2-associated ovarian cancer in December 2016. A phase II study found that continuous dosing provided better response rates than intermittent dosing in women with pathogenic BRCA-associated breast and ovarian cancer.[
The ARIEL-2 phase II study found that rucaparib was effective in the treatment of recurrent, high-grade, platinum-sensitive ovarian cancer in women with BRCA variants, but also in BRCA wild-type women with high genomic loss of heterozygosity (LOH), which is a likely marker of HRD cancers. The study enrolled 206 women, of whom 40 had germline pathogenic variants or somatic variants in BRCA. An additional 82 were BRCA wild-type but had high LOH. Median PFS was significantly longer in the BRCA variant subgroup (12.8 mo) (HR, 0.27; 95% CI, 0.16–44), and the high LOH subgroup (5.8 mo) (HR, 0.62; 95% CI, 0.42–0.90), compared with the low LOH subgroup (5.2 mo). The authors concluded that both BRCA variant status and LOH score, as a surrogate for HRD, were molecular predictors of rucaparib sensitivity in women with recurrent, platinum-sensitive, high-grade ovarian cancer.[
A phase III trial assessed rucaparib versus placebo in 576 women with recurrent, platinum-sensitive, high-grade ovarian cancer after response to second line, or greater, platinum chemotherapy. The study found that 196 women had BRCA pathogenic variants: 130 germline variants and 56 somatic variants. Median PFS of women in the rucaparib group was 10.8 versus 5.4 months (HR, 0.35; 95% CI, 0.30–0.45). Median PFS was the most prolonged in BRCA-associated ovarian cancer: 16.6 months in the rucaparib group versus 5.4 months in the placebo group (HR, 0.23; 95% CI, 0.16–0.34). In women with HRD cancers, the median PFS was 13.6 versus 5.4 months (HR, 0.32; 95% CI, 0.24–0.42). On the basis of these data, the authors concluded that platinum sensitivity alone was a sufficient marker to predict benefit from rucaparib in women with advanced high-grade ovarian cancer, without requiring additional HRD or BRCA testing.[
Niraparib
Niraparib is a selective inhibitor of PARP-1 and -2. A phase I dose-finding study observed a response rate of 42% with 300 mg daily in women with recurrent, BRCA-associated solid tumors.[
More mature data are necessary to determine whether platinum sensitivity alone is a marker of response to PARP inhibitors in women with BRCA pathogenic variants, and the optimal timing of PARP inhibitors as treatment or as maintenance therapy. HRD status may also be used to predict response to PARP treatment on the basis of a better understanding of the multiple genes involved in homologous repair pathways.
Level of evidence: 3dii
Treatment Strategies for Prostate Cancer
For more information on treating BRCA1/BRCA2 carriers diagnosed with prostate cancer, see the BRCA1 and BRCA2 and the Impact of Germline Genetics on Management and Treatment of Metastatic Prostate Cancer sections in Genetics of Prostate Cancer.
References:
Prognosis and Outcomes forBRCA1/2-Associated Female Breast Cancer
BRCA1- and BRCA2-associated breast cancers seem to have similar prognoses as sporadic breast cancers. Although BRCA1 carriers with breast cancer show slightly worse overall survival (OS) outcomes across multiple meta-analyses (for more information, see Table 4), the clinical relevance of this information is not yet clear. Future studies are needed to analyze prognosis after routine use of poly (ADP-ribose) polymerase inhibitor therapy.
Study Citation | Total Number of Studies | Total Number of Patients | BRCA1/BRCA2Carrier Breakdown | Follow-up Period | OS Values:BRCA1Carriers | OS Values:BRCA2 Carriers | Other Studied Survival Values | Study Caveats |
---|---|---|---|---|---|---|---|---|
BCSS = breast cancer–specific survival; CI = confidence interval; DFS = disease-free survival; DMFS = distant metastasis–free survival; EFS = event-free survival; HR = hazard ratio; OS = overall survival; PFS = progression-free survival; RFS = relapse-free survival. | ||||||||
Zhong et al. (Clinical Cancer Research, 2015)[ |
13 | 10,016 | 890BRCA1 carriers, 342BRCA2carriers, 8,784 noncarriers | Follow-up period of 4.5 to 7.9 y | BRCA1carriers had slightly worse OS values than noncarriers (HR, 1.5; 95% CI, 1.11–2.04) | BRCA2carriers did not have a significant difference in OS when compared with noncarriers (HR, 0.97; 95% CI, 0.78–1.22) | PFS | Studies were conducted from 2000 to 2013.BRCA1 carriers did not have consistently worse OS values when taking treatment into account |
Zhu et al. (Oncotarget, 2016)[ |
34 | 297,402 | 29,402BRCA1/BRCA2carriers | BRCA1: 7 studies with follow-up periods of <5 y, 10 studies with follow-up periods of >5 y;BRCA2: 3 studies with follow-up periods of <5 y, 5 studies with follow-up periods of >5 y | BRCA1carriers had slightly worse OS values than non-carriers (HR, 1.69; 95% CI, 1.35–2.12) | BRCA2 carriers had slightly worse OS values than noncarriers (HR, 1.50; 95% CI, 1.03–2.19) | BCSS, EFS | Studies were conducted from 1996 to 2014 |
Baretta et al. (Medicine [Baltimore], 2016)[ |
60 | 105,220 | 3,588BRCA1/BRCA2 carriers | Follow-up period not discussed in study | BRCA1carriers had slightly worse OS values than noncarriers (HR, 1.3; 95% CI, 1.11–1.52) | BRCA2 carriers did not have a significant difference in OS when compared with noncarriers (HR, 0.98; 95% CI, 0.76–1.25) | BCSS, RFS, DMFS | Studies were conducted from 1996 to 2013. An association was found betweenBRCA1/BRCA2carriers and decreased OS values (HR, 1.19; 95% CI, 1.04–1.35) |
Liu et al. (Breast Cancer Research and Treatment, 2021)[ |
30 | 35,972 | 3,402BRCA1/BRCA2 carriers | 4 studies with follow-up periods of <5 y, 8 studies with follow-up periods of >5 y | BRCA1carriers had slightly worse OS values than noncarriers (HR, 1.2; 95% CI, 1.08–1.33) | BRCA2 carriers did not have a significant difference in OS when compared with noncarriers (HR, 1.17; 95% CI, 0.99–1.39) | DFS, BCSS, DMFS | Studies were conducted from 2007 to 2017 |
Associations between BRCA pathogenic variants and prognosis may be specific to a breast cancer's hormone receptor (HR) subtype (i.e., HR-positive, triple negative, etc.). In a real-world study of patients with metastatic breast cancer from 2008 to 2016, BRCA variants were associated with improved progression-free survival (PFS) and OS values in triple-negative breast cancers (hazard ratio [HR], 0.76; 95% confidence interval [CI], 0.60–0.97; P = .027), but worse PFS values in HR-positive breast cancers (HR, 1.23; 95% CI, 1.03–1.46; P = .024).[
Prognosis and Outcomes forBRCA1/2-Associated Ovarian Cancer
Key points:
While ovarian cancer associated with BRCA1/BRCA2 pathogenic variants is typically associated with poor prognostic factors, several studies have found an improved survival rate in these individuals. A meta-analysis, which included literature up to 2021, compared BRCA-positive and BRCA-negative patients.[
Optimal treatment for ovarian cancer includes a combination of surgery and chemotherapy. In a study of consecutive patients with ovarian cancer in which germline BRCA1/BRCA2 statuses were available, 71.8% of patients with stage III/stage IV disease underwent primary debulking surgery, with 70.4% of patients achieving complete macroscopic tumor resection (R0 resection).[
In 2011, a significant survival advantage was seen in a case-control study among women with non-AJ BRCA1/BRCA2 pathogenic variants.[
In contrast, several studies have not found improved OS among ovarian cancer patients with BRCA1/BRCA2 pathogenic variants. A large series of unselected Canadian and American patients were tested for BRCA1 and BRCA2 pathogenic variants.[
Compelling data suggest a short-term survival advantage in BRCA1/BRCA2 carriers. However, long-term outcomes are yet to be established. Optimal surgery remains a cornerstone of care in this patient population. Larger studies, including the use of maintenance PARP inhibitors with longer follow-up time, are needed.
References:
While not homologous genes, both BRCA1 and BRCA2 have an unusually large exon 11 and translational start sites in exon 2. BRCA1 and BRCA2 appear to behave like tumor suppressor genes. In tumors associated with both BRCA1 and BRCA2 pathogenic variants, there is often loss of the wild-type allele.
Discovery and Historical Overview
In 1990, a susceptibility gene for breast cancer was mapped by genetic linkage to the long arm of chromosome 17, in the interval 17q12-21.[
A second breast cancer susceptibility gene, BRCA2, was localized to the long arm of chromosome 13 through linkage studies of 15 families with multiple cases of breast cancer that were not linked to BRCA1. BRCA2 is a large gene with 27 exons that encode a protein of 3,418 amino acids.[
BRCA1/2Function
Most BRCA1 and BRCA2 pathogenic variants are predicted to produce a truncated protein product, and thus loss of protein function, although some missense pathogenic variants cause loss of function without truncation. Because inherited breast/ovarian cancer is an autosomal dominant condition, individuals with a BRCA1 or BRCA2 pathogenic variant on one copy of chromosome 17 or 13 also carry a normal allele on the other paired chromosome. In most breast and ovarian cancers that have been studied from carriers of pathogenic variants, deletion of the normal allele results in loss of all function, leading to the classification of BRCA1 and BRCA2 as tumor suppressor genes. In addition to their roles as tumor suppressor genes, BRCA1 and BRCA2 are involved in myriad functions within cells, including homologous DNA repair, genomic stability, transcriptional regulation, protein ubiquitination, chromatin remodeling, and cell cycle control.[
References:
The PDQ cancer information summaries are reviewed regularly and updated as new information becomes available. This section describes the latest changes made to this summary as of the date above.
Genetics
Added text to state that BRCA1/BRCA2-associated cancer risks are inherited in an autosomal dominant manner.
Added Related Conditions as a new subsection.
Management of Cancer Risks in BRCA1/2 Carriers
Added level of evidence 2aii.
Added Occult cancers and premalignant lesions found during risk-reducing salpingo-oophorectomy (RRSO) as a new subsection.
Added Outcomes of occult lesions after RRSO as a new subsection.
Added Timing of RRSO as a new subsection.
Added Concomitant hysterectomy at time of RRSO as a new subsection.
Added Morbidity, mortality, and quality of life considerations after RRSO as a new subsection.
The Risk-reducing bilateral salpingectomy subsection was renamed from Bilateral salpingectomy.
Added text to state that a prospective, nonrandomized, controlled trial from the Netherlands compared quality of life in women who underwent salpingectomy versus those who underwent standard RRSO. After 1 year of follow-up, women whose ovaries were retained had better quality of life, even when compared with women who took estrogen after RRSO (cited Steenbeek et al. as reference 135).
Added level of evidence 4b.
Updated Table 3, Available Clinical Practice Guidelines for Hereditary Breast and Ovarian Cancer, with new recommendations from the European Society for Medical Oncology and the National Society of Genetic Counselors (cited Sessa et al. as reference 154 and Berliner et al. as reference 155).
Prognosis and Outcomes for BRCA1/2 Carriers
The Prognosis and Outcomes for BRCA1/2-Associated Ovarian Cancer subsection was extensively revised.
This summary is written and maintained by the
Purpose of This Summary
This PDQ cancer information summary for health professionals provides comprehensive, peer-reviewed, evidence-based information about BRCA1/BRCA2 (hereditary breast and ovarian cancer) cancer risks and management. It is intended as a resource to inform and assist clinicians in the care of their patients. It does not provide formal guidelines or recommendations for making health care decisions.
Reviewers and Updates
This summary is reviewed regularly and updated as necessary by the
Board members review recently published articles each month to determine whether an article should:
Changes to the summaries are made through a consensus process in which Board members evaluate the strength of the evidence in the published articles and determine how the article should be included in the summary.
The lead reviewers for BRCA1 and BRCA2 are:
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Levels of Evidence
Some of the reference citations in this summary are accompanied by a level-of-evidence designation. These designations are intended to help readers assess the strength of the evidence supporting the use of specific interventions or approaches. The PDQ Cancer Genetics Editorial Board uses a formal evidence ranking system in developing its level-of-evidence designations.
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PDQ® Cancer Genetics Editorial Board. PDQ BRCA1 and BRCA2. Bethesda, MD: National Cancer Institute. Updated <MM/DD/YYYY>. Available at:
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