Clinical Pearls & Morning Reports
For patients presenting with a pancreatic soft-tissue mass, imaging studies help to organize the differential diagnosis into three categories: extrapancreatic, cystic, and solid processes. Read the NEJM Case Records of the Massachusetts General Hospital here.
Q: What entities should be considered when a pancreatic soft-tissue mass is discovered?
A: Extrapancreatic masses include masses that are caused by regional lymphadenopathy and periampullary masses (ampullary, duodenal, and bile-duct neoplasms); these may be difficult to distinguish from intrinsic pancreatic lesions. Cystic pancreatic masses include retention cysts, intraductal papillary mucinous neoplasms, mucinous cystic neoplasms, and serous cystic neoplasms. Solid pancreatic masses include exocrine pancreatic cancer, pancreatic neuroendocrine tumors, autoimmune pancreatitis, metastatic cancer (notably renal-cell carcinoma and melanoma), lymphoma, focal pancreatitis, and solid pseudopapillary neoplasms.
Q: Are the imaging features of pancreatic neuroendocrine tumors similar to those of pancreatic adenocarcinoma?
A: Neuroendocrine tumors are often well circumscribed without vascular encasement and rarely cause pancreatic duct obstruction. Pancreatic neuroendocrine tumors typically appear as hypervascular masses on CT or MRI and are best identified on arterial phase images. Hypoenhancement of a pancreatic mass is more characteristic of adenocarcinoma.
A: Exocrine pancreatic cancer is diagnosed in more than 60,000 people in the United States annually and represents the fourth leading cause of cancer death. The majority of cases are classified as ductal adenocarcinoma. Surgery remains the only potentially curative treatment; approximately 15 to 20% of patients have surgically resectable disease at the time of presentation. The disease is most likely to occur in adults who are in the sixth or seventh decade of life and is relatively rare in adults younger than 40 years of age. Genetic counseling and testing for a germline mutation are recommended in all patients who receive a diagnosis of pancreatic cancer. The percentage of patients with exocrine pancreatic cancer who harbor a germline mutation ranges from 4 to 20%, with variants in BRCA1 and BRCA2 being most common.
A: The primary goal of adjuvant, or postoperative, radiation therapy for any cancer is to decrease the risk of local recurrence. The role of radiation therapy after definitive surgical resection for pancreatic cancer is controversial. Adjuvant radiation therapy has been shown to be effective in decreasing the risk of local recurrence and usually does not lead to acute or late side effects. However, one large, randomized trial conducted in Europe suggested an overall survival detriment with the addition of adjuvant chemoradiotherapy, thereby definitively closing the door on adjuvant radiation therapy in Europe. Given some limitations to this study, the debate regarding the role of adjuvant radiation therapy remains unsettled in the United States. A phase 3, randomized trial conducted in the United States addressed the question of adjuvant radiation therapy by comparing chemotherapy alone with chemotherapy followed by chemoradiotherapy. This study was stopped early because of poor accrual; however, the results are eagerly awaited.