Cancer is a disease in which cells grow in an abnormal way. Normally, the cells divide in a controlled manner. If cells keep dividing when new cells are not needed, a mass of tissue called a tumor forms.

A tumor can be benign or malignant. A benign tumor is not cancer and will not spread to other parts of the body. A malignant tumor is cancer and will invade and damage the tissue around it. The cancer cells can also enter the lymph and blood streams, spreading to other parts of the body. Pancreatic cancer is the development of malignant cells in the pancreas.

Cancer Cell Growth

Cancer Cell Growth
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The pancreas is an organ that sits behind and to the right of the stomach. It is near the liver, gallbladder, and intestines and is an important part of the digestive system. It plays a crucial role in the body’s ability to process food, making it able to generate and use energy.

Sections of the pancreas:

  • Head—on the right side, closest to the first part of the small intestine
  • Body—in the middle, located behind the stomach
  • Tail—on the left side, closest to the spleen

The Pancreas

The Pancreas
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The pancreas is made up of two different types of cells, endocrine and exocrine. Each cell type has a different function. The endocrine, or islet cells, produce a number of different chemicals called hormones. Hormones enter the bloodstream and travel throughout the body. They help manage a number of body functions and balance how the body works. For example, the pancreas makes insulin. This hormone breaks down and uses or stores sugars from food.

The exocrine cells of the pancreas make digestive juices that help break down food in the small intestine. The juices travel from the pancreas through a system of ducts into the small intestine. These digestive juices help process fat, protein, and carbohydrates in food.

Pancreatic cancer tumors can cause blockages in the pancreas. If digestive juices and/or insulin are blocked, it is possible to not get enough nutrition even when eating normally. If the tumor grows beyond the pancreas, the cancer can pass into nearby structures, such as the intestines, liver, or stomach. The cancer can cause damage and interfere with their function as well. The cancer can also spread to lymph nodes or blood vessels, which can carry cancer cells to other areas of the body. The most common sites for pancreatic cancer to spread to are the lining of the abdominal cavity, liver, and lungs.

There are several different types of pancreatic cancer based on the specific type of cells and where the cancer starts. Types of pancreatic cancers include:

  • Ductal adenocarcinoma—Develops in the ducts that pass digestive juices. This type makes up nearly all pancreatic cancers.
  • Acinar cell carcinoma—Arise from the exocrine cells that make pancreatic enzymes for digestion. There are other, more rare types of exocrine cancers. They are named for where they start and how they appear under a microscope. These include:
    • Adenosquamous carcinoma
    • Squamous cell carcinoma
    • Signet ring cell carcinoma
    • Undifferentiated carcinoma with or without giant cells
  • Pancreatic neuroendocrine tumors (PanNET)—Arise from the endocrine or islet cells of the pancreas. These tumors can also be benign, but it is often hard to determine, even with a microscope. It is possible that cancer cannot be diagnosed until the tumor spreads from the original site. There are different types of PanNets, including:
    • Functioning—Make up half of PanNet tumors. The tumors make hormones and can be found in the digestive tract. They are named for hormone that is produced by the tumor cells, such as gastrinoma (stomach) or insulinoma (pancreas).
    • Non-functioning—Tumors do not cause symptoms because they do not make enough excess hormones. As a result, they may not be found until they grow to a large size.
  • Ampullary—Starts in an area of the bile duct where it empties into the small intestine. In general, it is found earlier than other types of pancreatic cancer.

This fact sheet focuses on ductal adenocarcinoma of the pancreas.