General Information About Childhood Thymoma and Thymic Carcinoma
Thymoma and thymic carcinoma originate within the epithelial cells of the thymus, resulting in an anterior mediastinal mass. The term thymoma is customarily used to describe neoplasms that show no overt atypia of the epithelial component. Thymic carcinoma or type C thymoma is a thymic epithelial tumor that exhibits clear-cut cytological atypia and histological features no longer specific to the thymus. Thymic carcinomas have a higher incidence of capsular invasion and metastases.[1,2,3] Other tumors that involve the thymus gland include lymphomas, germ cell tumors, carcinomas, and carcinoids. Hodgkin lymphoma and non-Hodgkin lymphoma may also involve the thymus and must be differentiated from true thymomas and thymic carcinomas.
Special Considerations for the Treatment of Children With Cancer
Cancer in children and adolescents is rare, although the overall incidence has been slowly increasing since 1975.[4] Referral to medical centers with multidisciplinary teams of cancer specialists experienced in treating cancers that occur in childhood and adolescence should be considered. This multidisciplinary team approach incorporates the skills of the following health care professionals and others to ensure that children receive treatment, supportive care, and rehabilitation that will achieve optimal survival and quality of life:
- Primary care physicians.
- Pediatric surgeons.
- Radiation oncologists.
- Pediatric medical oncologists/hematologists.
- Rehabilitation specialists.
- Pediatric nurse specialists.
- Social workers.
- Child-life professionals.
- Psychologists.
For information about supportive care for children and adolescents with cancer, see the summaries on Supportive and Palliative Care.
The American Academy of Pediatrics has outlined guidelines for pediatric cancer centers and their role in the treatment of pediatric patients with cancer.[5] At these pediatric cancer centers, clinical trials are available for most types of cancer that occur in children and adolescents, and the opportunity to participate is offered to most patients and their families. Clinical trials for children and adolescents diagnosed with cancer are generally designed to compare potentially better therapy with current standard therapy. Most of the progress made in identifying curative therapy for childhood cancers has been achieved through clinical trials. Information about ongoing clinical trials is available from the NCI website.
Dramatic improvements in survival have been achieved for children and adolescents with cancer. Between 1975 and 2020, childhood cancer mortality decreased by more than 50%.[6,7,8] Childhood and adolescent cancer survivors require close monitoring because side effects of cancer therapy may persist or develop months or years after treatment. For information about the incidence, type, and monitoring of late effects in childhood and adolescent cancer survivors, see Late Effects of Treatment for Childhood Cancer.
Childhood cancer is a rare disease, with about 15,000 cases diagnosed annually in the United States in individuals younger than 20 years.[9] The U.S. Rare Diseases Act of 2002 defines a rare disease as one that affects populations smaller than 200,000 people. Therefore, all pediatric cancers are considered rare.
The designation of a rare tumor is not uniform among pediatric and adult groups. In adults, rare cancers are defined as those with an annual incidence of fewer than six cases per 100,000 people. They account for up to 24% of all cancers diagnosed in the European Union and about 20% of all cancers diagnosed in the United States.[10,11] Also, the designation of a pediatric rare tumor is not uniform among international groups, as follows:
These rare cancers are extremely challenging to study because of the low number of patients with any individual diagnosis, the predominance of rare cancers in the adolescent population, and the lack of clinical trials for adolescents with rare cancers.
Information about these tumors may also be found in sources relevant to adults with cancer, such as Thymoma and Thymic Carcinoma Treatment.
References:
- Carretto E, Inserra A, Ferrari A, et al.: Epithelial thymic tumours in paediatric age: a report from the TREP project. Orphanet J Rare Dis 6: 28, 2011.
- Kelly RJ, Petrini I, Rajan A, et al.: Thymic malignancies: from clinical management to targeted therapies. J Clin Oncol 29 (36): 4820-7, 2011.
- Suster S, Moran CA: Thymoma classification: current status and future trends. Am J Clin Pathol 125 (4): 542-54, 2006.
- Smith MA, Seibel NL, Altekruse SF, et al.: Outcomes for children and adolescents with cancer: challenges for the twenty-first century. J Clin Oncol 28 (15): 2625-34, 2010.
- American Academy of Pediatrics: Standards for pediatric cancer centers. Pediatrics 134 (2): 410-4, 2014. Also available online. Last accessed December 8, 2022.
- Smith MA, Altekruse SF, Adamson PC, et al.: Declining childhood and adolescent cancer mortality. Cancer 120 (16): 2497-506, 2014.
- National Cancer Institute: NCCR*Explorer: An interactive website for NCCR cancer statistics. Bethesda, MD: National Cancer Institute. Available online. Last accessed December 6, 2022.
- Surveillance Research Program, National Cancer Institute: SEER*Explorer: An interactive website for SEER cancer statistics. Bethesda, MD: National Cancer Institute. Available online. Last accessed September 7, 2022.
- Ward E, DeSantis C, Robbins A, et al.: Childhood and adolescent cancer statistics, 2014. CA Cancer J Clin 64 (2): 83-103, 2014 Mar-Apr.
- Gatta G, Capocaccia R, Botta L, et al.: Burden and centralised treatment in Europe of rare tumours: results of RARECAREnet-a population-based study. Lancet Oncol 18 (8): 1022-1039, 2017.
- DeSantis CE, Kramer JL, Jemal A: The burden of rare cancers in the United States. CA Cancer J Clin 67 (4): 261-272, 2017.
- Ferrari A, Brecht IB, Gatta G, et al.: Defining and listing very rare cancers of paediatric age: consensus of the Joint Action on Rare Cancers in cooperation with the European Cooperative Study Group for Pediatric Rare Tumors. Eur J Cancer 110: 120-126, 2019.
- Pappo AS, Krailo M, Chen Z, et al.: Infrequent tumor initiative of the Children's Oncology Group: initial lessons learned and their impact on future plans. J Clin Oncol 28 (33): 5011-6, 2010.