Pancreatic cancer is a disease in which normal cells in the pancreas stop working correctly and grow uncontrollably. These cancerous cells can build up and form a mass called a tumor. As it grows, a pancreatic tumor can affect the function of the pancreas, grow into nearby blood vessels and organs, and eventually metastasize (spread) to other parts of the body.
About the pancreas
The pancreas is a pear-shaped gland located in the abdomen between the stomach and the spine. It is about six inches in length and is made up of two major components:
The exocrine component, made up of ducts and acini (small sacs on the end of the ducts), makes enzymes (specialized proteins) that are released into the small intestine to help the body digest and break down food, particularly fats.
The endocrine component of the pancreas is made up of specialized cells lumped together in islands in the organ, called islets of Langerhans. These cells make specific hormones, most importantly insulin, the substance that helps control the amount of sugar in the blood.
Types of pancreatic cancer
There are several types of pancreatic cancer, depending on whether the cancer began in the exocrine or endocrine component.
Exocrine tumors. These are the most common type of pancreatic cancer. About 95% of people with pancreatic cancer have adenocarcinoma, which starts in gland cells. These tumors usually start in the ducts of the pancreas, called ductal adenocarcinoma, or, much less commonly, in the acini, called acinar adenocarcinoma.
Much rarer types of exocrine pancreatic tumors include: adenosquamous carcinomas, squamous cell carcinomas, and giant cell carcinomas.
Endocrine tumors. These are also called islet cell tumors or pancreatic neuroendocrine tumors (PNETs). They are much less common than exocrine tumors, making up about 1% of pancreatic cancers. A pancreatic neuroendocrine tumor can be functioning, meaning it makes hormones, or nonfunctioning, meaning it doesn’t make hormones. A functioning neuroendocrine tumor is named based on the hormone the cells normally make:
Insulinoma
Glucagonoma
Gastrinoma
Somatostatinoma
VIPomas
PPomas
This section covers pancreatic ductal adenocarcinoma. To learn more about tumors that start in the endocrine component of the pancreas, read about islet cell tumors and neuroendocrine tumors.
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