Learn about the medical, dental, pharmacy, behavioral, and voluntary benefits your employer may offer.
Incidence and Mortality
Pancreatic neuroendocrine tumors (NETs) are uncommon cancers with about 1,000 new cases per year in the United States.[
Pathogenesis
Tumors of the endocrine pancreas are a collection of tumor cell types collectively referred to as pancreatic NETs. These tumors originate in islet cells. Although they may be similar or identical in histological appearance to carcinoid tumors of the gastrointestinal tract, differences in their underlying biology and likely differences in response to therapeutic agents suggest that they should be treated and investigated as a distinct entity.[
Most pancreatic NETs are sporadic, but some occur as part of the autosomal dominant multiple endocrine neoplasia type 1 (MEN1) inherited syndrome. This syndrome consists of tumors of the anterior pituitary, parathyroid, and endocrine pancreas glands and is a result of inactivation of the MEN1 tumor suppressor gene located on chromosome 11q13.[
Islet tumors may either be functional (produce one or more active hormones) or nonfunctional.[
Prognostic Factors
Most islet cell cancers are functional, but about 15% are nonfunctional, with presentations similar to the far more common exocrine adenocarcinomas of the pancreas.[
Nonfunctional tumors tend to present at later clinical stages with symptoms attributable to mass effect or metastases.[
Diagnostics
The potential long delays between initial symptoms and diagnosis and the varied effects of the polypeptides secreted often necessitate involvement of multiple surgical and medical subspecialties. Surgery is the only curative modality and is often used, even in patients with metastatic disease, to alleviate the symptoms of hormonal hypersecretion.[
Tumor localization and staging studies include imaging with computed tomography (CT) with or without magnetic resonance imaging (MRI), and endoscopic ultrasonography. Somatostatin-receptor scintigraphy and single-photon emission CT may be useful adjuncts. However, somatostatin-receptor scintigraphy is less useful in localizing insulinomas versus other pancreatic NETs, since insulinomas often have a low density of somatostatin receptors.[
Some of the tumor types have unique characteristics that require specific approaches in their diagnosis and initial evaluation.
Gastrinoma
Diagnosis is dependent on elevated serum gastrin and elevated gastric acid levels. Provocative testing with calcium and secretin shows considerable overlap, and the value of these tests is limited. Zollinger-Ellison syndrome is a condition of unrelenting peptic ulcer disease, diarrhea, and gastric hyperacidity, associated with a gastrin-producing tumor. It accounts for less than 1% of all peptic ulcer disease. About 15% to 35% of gastrinomas are associated with MEN1 syndrome and up to 50% are malignant. Up to 33% of patients with gastrinomas have liver metastases.[
Diagnostic tests:
Insulinoma
Insulinomas are far more likely to be benign than malignant. Only 10% of insulinomas are multiple, and only 10% are malignant. About 5% to 8% are associated with MEN1 syndrome.[
The approach to management depends on carefully performed preoperative localization studies and the findings at exploratory laparotomy. In a retrospective case series of 30 patients with 32 pancreatic insulinomas, the combination of preoperative, dual-phase, thin-section multidetector CT and endoscopic sonography correctly identified and localized all of the tumors.[
Glucagonoma
Glucagonoma is the third most common endocrine-secreting islet cell tumor. About 75% of glucagonomas are malignant.[
Miscellaneous islet cell tumors
These tumors are rare but have defined clinical syndromes associated with specific production of polypeptide hormone production by islet cell tumors. Because of their rarity and similar approaches to management, they are grouped in the section on treatment. Miscellaneous tumors include:
VIPoma is characterized by watery diarrhea, hypokalemia, and achlorhydria. A serum vasoactive intestinal peptide (VIP) greater than 200 pg/mL is diagnostic.[
These tumors are particularly rare. They often present with diarrhea, steatorrhea, diabetes, and/or gallstones. Decreased pancreatic secretion of enzymes and bicarbonate accounts for the diarrhea and steatorrhea. Somatostatin-mediated inhibition of cholecystokinin leads to gallstone formation. Somatostatin also inhibits insulin, producing hyperglycemia. The diagnosis is made by a fasting serum somatostatin level greater than 100 pg/mL. CT scan, MRI, and endoscopic ultrasound can usually help localize and stage the tumor. Most of these tumors are malignant and have metastases at diagnosis.
References:
Islet Cells | Secreted Active Agent | Tumor and Syndrome |
---|---|---|
5-HT = serotonin; ACTH = adrenocorticotropin hormone; MSH = melanocyte-stimulating hormone; VIP = vasoactive intestinal peptide; WDHA = watery diarrhea, hypokalemia, and achlorhydria. | ||
Alpha | Glucagon | Glucagonoma (diabetes, dermatitis) |
Beta | Insulin | Insulinoma (hypoglycemia) |
Delta | Somatostatin | Somatostatinoma (mild diabetes); diarrhea/steatorrhea; gallstones |
D | Gastrin | Gastrinoma (peptic ulcer disease) |
A→D | VIP and/or other undefined mediators | WDHA |
5-HT | Carcinoid | |
ACTH | Cushing disease | |
MSH | Hyperpigmentation | |
Interacinar Cells | Secreted Active Agent | Tumor and Syndrome |
F | Pancreatic polypeptide | Multiple hormonal syndromes |
EC | 5-HT | Carcinoid |
American Joint Committee on Cancer (AJCC) Stage Groupings and TNM Definitions
The AJCC has designated staging by TNM (tumor, node, metastasis) classification to define pancreatic neuroendocrine tumors (islet cell tumors).[
Stage | TNM | Definition |
---|---|---|
T = primary tumor; N = regional lymph node; M = distant metastasis. | ||
a Reprinted with permission from AJCC: Neuroendocrine Tumors of the Pancreas. In: Amin MB, Edge SB, Greene FL, et al., eds.:AJCC Cancer Staging Manual. 8th ed. New York, NY: Springer, 2017, pp. 407–19. | ||
b The explanation for superscript b is at the end of Table 5. | ||
I | T1, N0, M0 | T1 = Tumor limited to the pancreas,b<2 cm. |
N0 = No regional lymph node involvement. | ||
M0 = No distant metastasis. |
Stage | TNM | Definition |
---|---|---|
T = primary tumor; N = regional lymph node; M = distant metastasis. | ||
a Reprinted with permission from AJCC: Neuroendocrine Tumors of the Pancreas. In: Amin MB, Edge SB, Greene FL, et al., eds.:AJCC Cancer Staging Manual. 8th ed. New York, NY: Springer, 2017, pp. 407–19. | ||
b The explanation for superscript b is at the end of Table 5. | ||
II | T2, N0, M0 | T2 = Tumor limited to the pancreas,b 2–4 cm. |
N0 = No regional lymph node involvement. | ||
M0 = No distant metastasis. | ||
T3, N0, M0 | T3 = Tumor limited to the pancreas,b>4 cm;or tumor invading the duodenum or common bile duct. | |
N0 = No regional lymph node involvement. | ||
M0 = No distant metastasis. |
Stage | TNM | Definition |
---|---|---|
T = primary tumor; N = regional lymph node; M = distant metastasis. | ||
a Reprinted with permission from AJCC: Neuroendocrine Tumors of the Pancreas. In: Amin MB, Edge SB, Greene FL, et al., eds.:AJCC Cancer Staging Manual. 8th ed. New York, NY: Springer, 2017, pp. 407–19. | ||
b The explanation for superscript b is at the end of Table 5. | ||
III | T4, N0, M0 | T4 = Tumor invading adjacent organs (stomach, spleen, colon, adrenal gland) or the wall of large vessels (celiac axis or the superior mesenteric artery). |
N0 = No regional lymph node involvement. | ||
M0 = No distant metastasis. | ||
Any T, N1, M0 | TX = Tumor cannot be assessed. | |
T1 = Tumor limited to the pancreas,b<2 cm. | ||
T2 = Tumor limited to the pancreas,b 2–4 cm. | ||
T3 = Tumor limited to the pancreas,b>4 cm;or tumor invading the duodenum or common bile duct. | ||
T4 = Tumor invading adjacent organs (stomach, spleen, colon, adrenal gland) or the wall of large vessels (celiac axis or the superior mesenteric artery). | ||
N1 = Regional lymph node involvement. | ||
M0 = No distant metastasis. |
Stage | TNM | Definition |
---|---|---|
T = primary tumor; N = regional lymph node; M = distant metastasis. | ||
a Reprinted with permission from AJCC: Neuroendocrine Tumors of the Pancreas. In: Amin MB, Edge SB, Greene FL, et al., eds.:AJCC Cancer Staging Manual. 8th ed. New York, NY: Springer, 2017, pp. 407–19. | ||
b Limited to the pancreas means there is no invasion of adjacent organs (stomach, spleen, colon, adrenal gland) or the wall of large vessels (celiac axis or the superior mesenteric artery). Extension of tumor into peripancreatic adipose tissue is NOT a basis for staging.Note: Multiple tumors should be designated as such (the largest tumor should be used to assign T category): if the number of tumors is known, use T(#); e.g., pT3(4) N0 M0; if the number of tumors is unavailable or too numerous, use them suffix, T(m); e.g., pT3(m) N0 M0. | ||
IV | Any T, Any N, M1 | TX = Tumor cannot be assessed. |
T1 = Tumor limited to the pancreas,b<2 cm. | ||
T2 = Tumor limited to the pancreas,b 2–4 cm. | ||
T3 = Tumor limited to the pancreas,b>4 cm;or tumor invading the duodenum or common bile duct. | ||
T4 = Tumor invading adjacent organs (stomach, spleen, colon, adrenal gland) or the wall of large vessels (celiac axis or the superior mesenteric artery). | ||
NX = Regional lymph nodes cannot be assessed. | ||
N0 = No regional lymph node involvement. | ||
N1 = Regional lymph node involvement. | ||
M1 = Distant metastases. | ||
–M1a = Metastasis confined to liver. | ||
–M1b = Metastases in at least one extrahepatic site (e.g., lung, ovary, nonregional lymph node, peritoneum, bone). | ||
–M1c = Both hepatic and extrahepatic metastases. |
References:
Localized Disease
If technically and medically feasible, primary management of endocrine tumors of the pancreas involves surgical resection with curative intent. Given the rare nature of these tumors, surgical approaches are based on case series and expert opinion rather than randomized controlled trials.[
Adjuvant therapy has no proven benefit and is, therefore, investigational. There have been no well-controlled trials of adjuvant therapy after complete tumor resection.[
Surgical Cytoreduction for Metastases
Surgery plays a role even in the setting of metastatic disease. The symptoms of metastatic functional pancreatic neuroendocrine tumors (NETs) may be ameliorated by the reduction of overall tumor burden through surgical debulking.
The liver is a common site of metastasis from pancreatic NETs. Because of the slow growth rate of many NETs, liver metastases are often resected when technically feasible. Resection of all grossly visible liver metastases can be associated with long-term survival and, in the case of symptomatic hormonally functional tumors, symptom relief.[
Alternative approaches to the management of liver metastases have been reported, including Gelfoam embolization or transarterial chemoembolization,[
Results from surgical resection series appear to be more favorable than with these techniques, and surgery is considered to be the standard approach to resectable liver metastases. However, there are no high-quality studies comparing the various approaches. A systematic review of evidence comparing liver resection versus other treatments for patients with resectable liver neuroendocrine metastases found no randomized trials, or even quasi-experimental, cohort, or case-control studies in which the patient population given the alternative therapies was similar enough to the surgery group to draw reliable conclusions.[
In most cases, liver metastases are not completely resectable. Cytoreductive surgery, with or without radiofrequency ablation or cryoablation, has been used to palliate symptoms. A systematic review found no randomized or quasi-randomized trials comparing cytoreductive surgery to other palliative approaches such as chemotherapy or tumor product inhibitors.[
Systemic Therapy for Advanced and Metastatic Disease
Somatostatin analogues may be effective in reducing the symptoms of functional tumors.[
Chemotherapy using drugs such as the following, either alone or in combination, has been shown to have antitumor effects, but evidence is weak or conflicting regarding the impact of chemotherapy on overall survival:[
A variety of systemic agents have shown biological or palliative activity, including:[
Nearly all of the evidence of activity is derived from case series.[Level of evidence C3] However, there are ongoing placebo-controlled randomized trials of everolimus [
Favorable responses have been reported in patients with advanced progressive pancreatic NETs after treatment with several radiolabeled somatostatin analogues in which the analogues octreotide, octreotate, lanreotide, or edotreotide are stably attached to the radionuclides indium In 111, yttrium Y 90, or lutetium Lu 177.[
As noted in each of the clinical situations, there is a paucity or absence of high-level evidence and a need for randomized controlled trials.[
Fluorouracil dosing
The DPYD gene encodes an enzyme that catabolizes pyrimidines and fluoropyrimidines, like capecitabine and fluorouracil. An estimated 1% to 2% of the population has germline pathogenic variants in DPYD, which lead to reduced DPD protein function and an accumulation of pyrimidines and fluoropyrimidines in the body.[
References:
The approach to treatment often depends on the results of preoperative localization studies and findings at exploratory laparotomy. At exploration, 85% of these tumors are found in the gastrinoma triangle with 40% on the surface of the pancreas and 40% outside of the pancreas. Only 15% are found within the substance of the pancreas. Percutaneous transhepatic venous sampling may occasionally provide accurate localization of single sporadic gastrinomas. Resection (enucleation of individual tumors, if technically feasible), and even excision of liver metastases, is associated with long-term cure or disease control.[
Treatment options:
Patients with hepatic-dominant disease and substantial symptoms caused by tumor bulk or hormone-release syndromes may benefit from procedures that reduce hepatic arterial blood flow to metastases (hepatic arterial occlusion with embolization or with chemoembolization). Such treatment may also be combined with systemic chemotherapy in selected patients. Treatment with proton pump inhibitors or H2 blocking agents may aid in control of peptic symptoms.
In the era of proton pump inhibitors and H2 blocking agents, the potentially lethal hyperacidity and hypersecretory states induced by excessive gastrin production can usually be controlled. In a series of 212 patients with Zollinger-Ellison syndrome (ZES), no patients died of causes related to acid hypersecretion. Only 2.3% of those patients had undergone total gastrectomy, and the study cohort had a long median follow-up period of 13.8 years. Although 32% of the patients died during the course of the study, only 50% of the 67 deaths were attributable to ZES-related causes. Those causes were mainly liver metastases with progressive anorexia and cachexia (67%) or secondary endocrine tumors consequent to multiple endocrine neoplasia type 1 syndrome. The development of bone or liver metastases (especially diffuse liver disease) or of ectopic Cushing syndrome during the study period predicted for decreased survival times.[
Current Clinical Trials
Use our
References:
Curative surgical excision, by open laparotomy or laparoscopy, is the treatment of choice when possible. The open surgical approach is used if the tumor is suspected to be malignant because en bloc lymphadenectomy is performed for malignant tumors without distant metastases. Intraoperative ultrasonography aids the localization of tumor extent and the relationship to other anatomical structures.[
Treatment options:
Patients with hepatic-dominant disease and substantial symptoms caused by tumor bulk or hormone-release syndromes may benefit from procedures that reduce hepatic arterial blood flow to metastases (hepatic arterial occlusion with embolization or with chemoembolization).[
Current Clinical Trials
Use our
References:
As with the other pancreatic neuroendocrine tumors, the mainstay of therapy is surgical resection, and extended survival is possible even when the disease is metastatic. Resection of metastases is also a consideration when feasible.[
Treatment options:
Patients with hepatic-dominant disease and substantial symptoms caused by tumor bulk or hormone-release syndromes may benefit from procedures that reduce hepatic arterial blood flow to metastases (hepatic arterial occlusion with embolization or with chemoembolization).[
Current Clinical Trials
Use our
References:
VIPoma
Immediate fluid resuscitation is often necessary to correct the electrolyte and fluid problems that occur as a result of the watery diarrhea, hypokalemia, and achlorhydria that patients experience. Somatostatin analogues are also used to ameliorate the large fluid and electrolyte losses. Once patients are stabilized, excision of the primary tumor and regional nodes is the first line of therapy for clinically localized disease. In the case of locally advanced or metastatic disease, where curative resection is not possible, debulking and removal of gross disease, including metastases, should be considered to alleviate the characteristic manifestations of vasoactive intestinal peptide overproduction.[
Somatostatinoma
Complete excision is the therapy of choice, if technically possible. However, metastases often preclude curative resection, and palliative debulking can be considered to relieve symptoms.[
Other Pancreatic Neuroendocrine Tumors
For these very rare tumors, complete surgical excision is the only curative option when technically possible. Debulking or somatostatin analogues are used for palliation of symptoms if the tumor is functional. For more information, see the Treatment Option Overview for Pancreatic Neuroendocrine Tumors (Islet Cell Tumors) section.
Current Clinical Trials
Use our
References:
There is no established therapy for pancreatic neuroendocrine tumors that recur or progress after previous therapy.[
Attempts at re-resection of local tumors that have recurred or re-resection of metastatic lesions may offer palliation, when technically feasible. Intra-arterial chemotherapy is a consideration for patients with liver metastases. Patients with hepatic-dominant disease and substantial symptoms caused by tumor bulk or hormone-release syndromes may benefit from continuous-infusion intra-arterial chemotherapy or procedures that reduce hepatic arterial blood flow to metastases (hepatic arterial occlusion with embolization or with chemoembolization).[
Current Clinical Trials
Use our
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.
Treatment Option Overview for Pancreatic Neuroendocrine Tumors (Islet Cell Tumors)
Added Fluorouracil dosing as a new subsection.
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 the treatment of pancreatic neuroendocrine tumors (islet cell tumors). 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 Pancreatic Neuroendocrine Tumors (Islet Cell Tumors) Treatment are:
Any comments or questions about the summary content should be submitted to Cancer.gov through the NCI website's
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 Adult Treatment Editorial Board uses a formal evidence ranking system in developing its level-of-evidence designations.
Permission to Use This Summary
PDQ is a registered trademark. Although the content of PDQ documents can be used freely as text, it cannot be identified as an NCI PDQ cancer information summary unless it is presented in its entirety and is regularly updated. However, an author would be permitted to write a sentence such as "NCI's PDQ cancer information summary about breast cancer prevention states the risks succinctly: [include excerpt from the summary]."
The preferred citation for this PDQ summary is:
PDQ® Adult Treatment Editorial Board. PDQ Pancreatic Neuroendocrine Tumors (Islet Cell Tumors) Treatment. Bethesda, MD: National Cancer Institute. Updated <MM/DD/YYYY>. Available at:
Images in this summary are used with permission of the author(s), artist, and/or publisher for use within the PDQ summaries only. Permission to use images outside the context of PDQ information must be obtained from the owner(s) and cannot be granted by the National Cancer Institute. Information about using the illustrations in this summary, along with many other cancer-related images, is available in
Disclaimer
Based on the strength of the available evidence, treatment options may be described as either "standard" or "under clinical evaluation." These classifications should not be used as a basis for insurance reimbursement determinations. More information on insurance coverage is available on Cancer.gov on the
Contact Us
More information about contacting us or receiving help with the Cancer.gov website can be found on our
Last Revised: 2024-08-16
This information does not replace the advice of a doctor. Ignite Healthwise, LLC, disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the
Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Ignite Healthwise, LLC.
Individual and family medical and dental insurance plans are insured by Cigna Health and Life Insurance Company (CHLIC), Cigna HealthCare of Arizona, Inc., Cigna HealthCare of Illinois, Inc., Cigna HealthCare of Georgia, Inc., Cigna HealthCare of North Carolina, Inc., Cigna HealthCare of South Carolina, Inc., and Cigna HealthCare of Texas, Inc. Group health insurance and health benefit plans are insured or administered by CHLIC, Connecticut General Life Insurance Company (CGLIC), or their affiliates (see
All insurance policies and group benefit plans contain exclusions and limitations. For availability, costs and complete details of coverage, contact a licensed agent or Cigna sales representative. This website is not intended for residents of New Mexico.