Pancreatic Cancer – Overview

Pancreatic cancer is a disease in which healthy cells in the pancreas stop working correctly and grow out of control. These cancerous cells can build up and form a mass called a tumor. A cancerous tumor is malignant, meaning it can grow and spread to other parts of the body. As it grows, a pancreatic tumor can affect the function of the pancreas, grow into nearby blood vessels and organs, and eventually spread to other parts of the body through a process called metastasis.

About the pancreas

The pancreas is a pear-shaped gland located in the abdomen between the stomach and the spine. It is made up of two major components:

The exocrine component is made up of ducts and small sacs called acini on the end of the ducts. This part of the pancreas makes specialized proteins called enzymes 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 cells lumped together in different locations within this part of the pancreas, called islets of Langerhans. These cells make specific hormones, most importantly insulin. Insulin is the substance that helps control the amount of sugar in the blood. This portion of the pancreas also makes other hormones, such as glucagon, somatostatin, pancreatic polypeptide (PP), and vasoactive intestinal peptide (VIP). Each of these hormones plays an important role in regulating the body’s metabolism.

Types of pancreatic cancer

There are several types of pancreatic cancer, depending on whether the cancer began in the exocrine or endocrine component. Rarely, other types of cancer can begin in the pancreas, such as lymphoma and sarcoma.

Exocrine tumors.

These are the most common type of pancreatic cancer. And adenocarcinoma is the most common type of exocrine tumor. These tumors usually start in the ducts of the pancreas, called ductal adenocarcinoma. Much less commonly, if the tumor begins in the acini, it is called acinar adenocarcinoma.

An increasingly common diagnosis is called intraductal papillary mucinous neoplasm (IPMN). An IPMN is a tumor that grows within the ducts of the pancreas and makes a thick fluid called mucin. IPMN is not cancerous when it begins but could become cancerous if not treated. Sometimes, an IPMN has already worsened and become a cancer by the time it is diagnosed.

Much rarer types of exocrine pancreatic tumors include: acinar cell carcinoma, adenosquamous carcinoma, colloid carcinoma, giant cell tumor, hepatoid carcinoma, mucinous cystic neoplasms, pancreatoblastoma, serous cystadenoma, signet ring cell carcinoma, solid and pseudopapillary tumors, squamous cell carcinoma, and undifferentiated carcinoma.

Endocrine tumors. These are also called pancreatic neuroendocrine tumors (PNETs) or islet cell tumors. They are much less common than exocrine tumors, making up about 1% of pancreatic cancers. A pancreatic neuroendocrine tumor can be functioning or nonfunctioning. A functioning tumor makes hormones. A nonfunctioning tumor does not make hormones. A functioning neuroendocrine tumor is named based on the hormone the cells normally make. These include:

Insulinoma
Glucagonoma
Gastrinoma
Somatostatinoma
VIPomas
PPomas