About the Pancreas
The pancreas is found in the abdomen, behind the stomach. It is surrounded by the small intestine, liver, and spleen.
Most of the pancreas consists of exocrine cells. These cells produce and secrete enzymes that aid in the breakdown of foods. Lipase breaks down fats, protease breaks down proteins, and amylase breaks down carbohydrates.
A small portion of the pancreas consists of endocrine cells. These cells produce and secrete hormones, including gastrin, which triggers release of acid in the stomach, and insulin, which helps lower the level of sugar in the blood.
What is Pancreatic Cancer?
When either exocrine or endocrine cells begin to grow abnormally they can turn into cancer. Cancer cells do not respond to regular cell growth, division, and death signals like they are supposed to. They also don’t organize normally. Instead they grow into a tumor, which may break through nearby tissues or spread to other parts of the body.
It is important to know whether a pancreatic tumor started in the exocrine cells or endocrine cells because there are different treatment strategies and prognoses for each type.
The term “pancreatic cancer” is often used to refer to cancer that started in the exocrine cells of the pancreas. Most pancreatic cancers are exocrine cancers that begin in the ducts that carry pancreas juices (and enzymes) to the common bile duct. The common bile duct empties into the duodenum, the first section of the small intestine. The most common of these cancers is adenocarcinoma. Nearly 95 percent of exocrine pancreatic cancers are adenocarcinomas. There are several other exocrine pancreatic cancers, also called non-endocrine pancreatic cancers.
What are Pancreatic Neuroendocrine Tumors?
Pancreatic cancers that start in the endocrine cells are called pancreatic neuroendocrine tumors (NETs). They are also known as neuroendocrine tumors of the pancreas or islet cell tumors. NETs can be either malignant (cancer) or benign (not cancer).
Malignant pancreatic NETs are very rare, accounting for about one percent of newly diagnosed pancreatic cancers. They often grow slower than exocrine pancreatic cancers. Some are called “functional” because they secrete hormones; some are “nonfunctional” because they don’t secrete hormones. Pancreatic NETs can often be cured.
There are several types of NETs, named for the type of endocrine cell where they begin. These are the most common functional NETs:
- Insulinoma, which makes too much of the hormone insulin
- Gastrinoma, which makes large amounts of the hormone gastrin
Pancreatic Cancer in the U.S.
While it is a serious disease, pancreatic cancer is relatively rare. The American Cancer Society estimates that about 44,000 people in the United States will be diagnosed with pancreatic cancer (either exocrine or endocrine) each year. Pancreatic cancer is the tenth most common cancer in men and women.