What Is Pancreatic Cancer?

Pancreatic cancer develops from rapidly growing, out-of-control cells in the pancreas. Your pancreas sits behind your stomach where the first part of your small intestine begins. Different types of tumors affect the pancreas, either in exocrine or endocrine cells. Your diagnosis of exocrine or endocrine cancer determines your treatment options. The two types of pancreatic cancer sound similar but actually lead to very different signs and symptoms. They are diagnosed using different tests, provide different outlooks and involve different treatments.

Exocrine Pancreatic Cancers

Most people with pancreatic cancer gain a diagnosis of exocrine pancreatic cancer. This type includes several subtypes:

• Pancreatic adenocarcinoma, affecting about 95 percent of exocrine pancreatic cancer patients and usually beginning in the pancreatic ducts
• Less common exocrine pancreatic cancers, including adenosquamous carcinomas, squamous cell carcinomas, signet ring cell carcinomas, undifferentiated carcinomas, and undifferentiated carcinomas with giant cells
• Ampullary cancer, developing in the region of the pancreas where the bile duct and pancreatic duct merge and empty into the small intestine

Endocrine Pancreatic Cancers

A less frequent pancreatic cancer diagnosis than exocrine cancer, tumors of the endocrine pancreas affect under five percent of pancreatic cancer patients. Some people call these cancers pancreatic neuroendocrine tumors or islet cell tumors. Pancreatic neuroendocrine tumors do not always lead to a cancer diagnosis, with some being benign.

Despite being a cancer of a small organ, endocrine pancreatic cancer includes many subtypes. These include:

• Functioning neuroendocrine tumors, affecting about half of all endocrine pancreatic cancer patients and featuring tumors producing hormones released into the bloodstream
  • Gastrinomas, with about half of these gastrin-producing cell tumors being cancerous
  • Insulinomas, usually benign tumors from insulin-producing cells
  • Glucagonomas, usually malignant tumors developed from glucagon-producing cells
  • Somatostatinomas, mostly cancerous tumors from somatostatin-producing cells
  • VIPomas, mostly cancerous tumors from vasoactive intestinal peptide (VIP)-producing cells
  • PPomas, mostly cancerous tumors from pancreatic polypeptide-producing cells
• Non-functioning neuroendocrine tumors, usually cancerous tumors often growing quite large before being found due to the lack of symptoms from non-production of hormones
• Carcinoid neuroendocrine tumors only rarely starting in the pancreas, producing serotonin or a serotonin precursor

Your treatment plan and outlook depend on the tumor type, stage of development and other factors. But pancreatic endocrine cancer usually provides a better outlook than exocrine cancers.