Pancreatic islet cell carcinoma
Pancreatic islet cell carcinoma |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Cancer of the endocrine pancreas includes a highly treatable and often curable collection of tumors.
Classification
Islet tumors may either be functional (produce one or more hormones) or nonfunctional. The majority of functioning tumors that produce insulin are benign; however, 90% of non-functioning tumors are malignant.
Many islet cell cancers are nonfunctional and produce symptoms from tumor bulk or metastatic dissemination. Because of the presence of several cell types in the pancreatic islet cells (alpha, beta, delta, A, B, C, D, E), the term islet cell tumors refers to at least five distinct cancers, which when functional, produce unique metabolic and clinical characteristics[1].
Pathophysiology
Pancreatic islet cell carcinoma is of 6 types:
- Gastrinoma
- Insulinoma
- Vasoactive intestinal peptide releasing tumor (VIPoma)
- Somatostatinoma
- Glucagonoma
- Non functional islet cell tumor
Epidemiology and Demographics
They are uncommon cancers with 200 to 1,000 new cases per year and occur in only 1.5% of detailed autopsy series.
Staging
Pancreatic cancer is staged according to the TNM staging system based on the primary tumor, lymph nodes involved and distant metastasis.
TNM Classification for Pancreatic Cancer: | |
---|---|
Primary tumor | |
TX | Primary tumor cannot be assessed |
T0 | No evidence of primary tumor |
Tis | Carcinoma in situ |
T1 | Tumor limited to the pancreas, ≤2 cm in greatest dimension |
T2 | Tumor limited to the pancreas, >2 cm in greatest dimension |
T3 | Tumor extends beyond the pancreas but without involvement of the celiac axis or the superior mesenteric artery |
T4 | Tumor involves the celiac axis or the superior mesenteric artery (unresectable primary tumor) |
Regional lymph nodes | |
NX | Regional lymph nodes cannot be assessed |
N0 | No regional lymph node metastasis |
N1 | Regional lymph node metastasis |
Distant metastases | |
MX | Distant metastasis cannot be assessed |
M0 | No distant metastasis |
M1 | Distant metastasis |
Treatment
Medical Therapy
Combination chemotherapy may provide effective palliation as well as increased survival in selected patients. In patients with indolent, slow-growing metastatic islet cell tumors, the best therapy may be careful observation and no treatment until palliation is required.
Surgery
Surgery is the only curative modality.[4,5] Even in those cases not resectable for cure, effective palliation may be achieved because of the slow-growing nature of the majority of these tumors and the potential use of antihormonal pharmacologic therapy (for example, cimetidine in the ulcer-producing Zollinger-Ellison syndrome).
Patients with multiple endocrine neoplasia syndrome type 1, an autosomal dominant condition in which 85% have pancreatic islet cell tumors, 90% have hyperparathyroidism, and 65% have pituitary tumors, are less likely to be cured by pancreatic resection than are patients with sporadic islet cell tumors. With the exception of pain relief from bone metastases, radiation therapy has a limited role in this disease[2].