What is pancreatic cancer?
Pancreatic cancer refers to tumors that start in the cells of the pancreas, an organ located behind your stomach that helps you digest food. Cancer develops when cells grow in an uncontrolled manner and form masses or tumors in the pancreas, instead of growing into healthy pancreatic tissue, which may also spread to other parts of the body. Tumors can interfere with the functions of the pancreas and cause pain and other symptoms.
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What is a pancreatic tumor?
Normally, cells only divide to form new cells when the body needs them, and the body destroys old cells that are no longer functioning properly. Mutuations in cell DNA can cause cells to grow and divide uncontrollably, or may prevent old cells from dying when necessary. The reasons these mutations occur are still being researched, but it is known that the mutations can either be inherited or acquired during life. When extra cells accumulate and form a mass, it is called a tumor. Tumors can be benign or malignant.
What is the difference between a benign tumor and cancer?
If a tumor remains in one place and stops growing, it is considered benign. Benign tumors do not possess the ability to invade other tissues and organs. This is why benign tumors are not cancerous. However, they can cause health problems by placing pressure on nearby organs, blood vessels, or nerves.
If a tumor continues to spread, it is considered malignant – also called cancer. Malignant tumors are dangerous because they can spread to other organs and tissues. The process of spreading beyond the original organ is called metastasis: if a tumor has spread to other tissues or organs, it is called metastatic (it has metastasized to other locations). Physicians assign the cancer a stage depending on how wide it has spread.
Tumors in the pancreas can either be exocrine tumors (about 95% of pancreatic cancers) or endocrine tumors (about 5% of pancreatic cancers).
What are exocrine tumors?
Pancreatic cancer can develop in any part of the pancreas. Pancreatic adenocarcinoma, also called pancreatic ductal adenocarcinoma, orPDAC, originates in the exocrine tissue (which constitutes the majority of the pancreas) and is the most common kind of pancreatic cancer (95%). Pancreatic adenocarcinoma arises from abnormal cells lining the pancreatic duct. These cells may form glands, or a collection of cells surrounding an empty space. Unless otherwise specified, nearly all accounts of pancreatic cancer refer to pancreatic ductal adenocarcinoma or PDAC.
Other rare forms of exocrine tumors include acinar cell carcinoma, adenosquamos carcinoma, and mucinous cystadenocarcinoma.
The information on this site refers mostly to exocrine tumors, and specifically pancreatic adenocarcinoma.
What are endocrine tumors?
Endocrine tumors are cancers that originate in the hormone-producing cells of the pancreas,* the islet of Langerhans cells. Because endocrine tumors begin in cells that produce hormones, the tumors themselves may produce hormones that cause symptoms in addition to the problems caused by the presence of an abnormal mass.
Of all pancreatic cancers, endocrine tumors account for less than 5%. They may also be called neuroendocrine or islet cell tumors. Islet cell tumors affect approximately 2500 people in the United States annually. Some of these tumors secrete excessive amounts of hormone and are referred to as functional neuroendocrine tumors. More common functional islet cell tumors include insulinomas and glucagonomas, whereas VIPomas and somatostatinomas are much more unusual. Nonfunctional tumors are less common and do not secrete excess hormones.
*Note: Endocrine tumors may also form in hormone-producing cells in other parts of the body such as the adrenal gland, thyroid, parathyroid, pituitary gland, lung and gastrointestinal tract.