What is pancreatic cancer?
The normal pancreas
The pancreas is an organ found deep in the body, behind the stomach. It is shaped a little bit like a fish. It is about 6 inches long and less than 2 inches wide. It goes across the belly (abdomen).
The pancreas contains 2 different kinds of glands. The exocrine glands make pancreatic “juice.” This juice has enzymes which break down fats and proteins in the foods you eat so the body can use them. Most of the cells in the pancreas are part of the exocrine system. A smaller number of cells in the pancreas are endocrine cells. These cells are arranged in clusters called islets. They make hormones like insulin that help balance the amount of sugar in the blood.
Types of pancreatic tumors
Both the exocrine and endocrine cells of the pancreas can form tumors. But tumors formed by the exocrine cells are much more common. When someone says that they have pancreatic cancer, they usually mean an exocrine pancreatic cancer. Not all of the tumors in the pancreas are cancer. A small number are not cancer (they are benign).
It is important to know whether a tumor is from the exocrine or endocrine part of the pancreas. Each type of tumor has its own signs and symptoms, is found using different tests, is treated in different ways, and has a different outlook for survival (prognosis).
Exocrine tumors are by far the most common type of pancreas cancer. Nearly all of these tumors are a kind called adenocarcinomas. (An adenocarcinoma is a cancer that starts in gland cells.) Treatment of cancer of the exocrine pancreas is mostly based on the stage of the cancer, not its exact type. The stage of the cancer describes how far it has progressed. Pancreatic cancer staging is described in the section “Staging for pancreatic cancer.”
A special type of cancer (called ampullary cancer) can start where the bile duct (from the liver) and the pancreatic duct empty into the small intestine (called the ampulla of Vater –see the drawing above). This type of cancer often causes signs such as yellowing of the skin and eyes, so it is usually found at an earlier stage than most pancreatic cancers. Finding it early means that the chances of successful treatment are better. Ampullary cancers are covered here with pancreatic cancer because their treatments are very much alike.
Tumors of the endocrine pancreas are much less common. They are known as islet cell tumors or neuroendocrine tumors and are divided into several sub-types. Most of these are not cancer (benign), but there are a few that are cancer.
The information here refers only to exocrine cancer and ampullary cancer. Please see our document, Pancreatic Cancer to learn more about neuroendocrine tumors of the pancreas.
Last Medical Review: 02/15/2013
Last Revised: 02/03/2014