摘要
Pancreatic cancer is the fourth leading cause of cancer death in the U.S. According to the Surveillance Epidemiology and End Results (SEER) program, the median age at diagnosis between 2003-2007 was 72 years of age, and the incidence of new cases diagnosed during this period in all races was 13.3 per 100,000 men and 10.5 per 100,000 women. The median age at death for pancreatic cancer during the same period was 73 years of age, and the mortality rate for all races was 12.3 per 100,000 men and 9.4 per 100,000 women. Pancreatic cancer has a 22.5% 5-year survival rate when localized to the pancreas at diagnosis, and it decreases to 1.9% when metastasized. The lifetime risk to develop pancreatic cancer is 1.41%, and it is the same for men and women. (National Cancer Institute, 2011) Different types of pancreatic cancers originate from different type of pancreatic cells. About 95% of pancreatic cancers originate from exocrine cells. Of these, the most common is pancreatic adenocarcinoma (about 95%). Other less common types of exocrine tumors are: adenosquamous carcinomas, squamous cell carcinomas, giant cell carcinomas, intraductal papillary mucinous neoplasms (IPMN), mucinous cystadenocarcinoma, pancreatoblastoma, cystadenocarcinoma and pseudopapillary tumors. About 5% of pancreatic cancers originate from endocrine cells, and are known as pancreatic neuroendocrine tumors (NETs). Each of these tumors is named according to the hormone they produce: insulinomas, glucagonomas, gastrinomas, somatostatinomas, VIPomas. (American Cancer Society, 2011) Cystic pancreatic lesions are common and have a wide range of malignant potential. These lesions include, but are not limited to, serous cystadenomas (low potential for malignancy), mucinous cystic neoplasms, and IPMN. Based on the degree of dysplasia, these neoplasms are classified into benign (adenomatous), low-grade malignant (borderline) and malignant (carcinoma in situ and invasive cancer). (Brugge et al, 2004)