what is pancreatic cancer
What Is The Pancreas?
The pancreas is a 6-inch long organ located behind the stomach in the back
of the abdomen. It is spongy and shaped somewhat like a fish, extended
horizontally across the abdomen. The head of the pancreas is on the right side
of the abdomen where the stomach is attached to the first part of the small
intestine (the duodenum). The tail of the pancreas - its narrowest part -
extends to the left side of the abdomen next to the spleen.
The pancreas contains exocrine and endocrine glands that create pancreatic
juices, hormones, and insulin. Pancreatic juices, or enzymes, made by the
exocrine glands are released into the intestines by way of a series of ducts in
order to help digest fat, proteins, and carbohydrates. Over 95% of the pancreas
is made up of exocrine glands and ducts. The endocrine cells are arranged in
small clusters called islets of Langerhans, which release insulin and glucagon
into the bloodstream. These two hormones manage levels of sugar in the blood.
When they are not working properly, the result is often diabetes.
What Is Pancreatic Cancer?
Cancer is a class of diseases characterized by out-of-control cell growth,
and pancreatic cancer occurs when this uncontrolled cell growth begins in the
pancreas. Rather than developing into healthy, normal pancreas tissue, these
abnormal cells continue dividing and form lumps or masses of tissue called
tumors. Tumors then interfere with the main functions of the pancreas. If a
tumor stays in one spot and demonstrates limited growth, it is generally
considered to be benign.
More dangerous, or malignant, tumors form when the cancer cells migrate to
other parts of the body through the blood or lymph systems. When a tumor
successfully spreads to other parts of the body and grows, invading and
destroying other healthy tissues, it is said to have metastasized. This process
itself is called metastasis, and the result is a more serious condition that is
very difficult to treat.
In the United States each year, over 30,000 people are diagnosed with
pancreatic cancer. Europe sees more than 60,000 diagnoses each year. Because
pancreatic cancer is usually diagnosed late into its development, the five-year
survival rate after diagnosis is less than 5%.
How Is Pancreatic Cancer Classified?
Pancreatic cancer is categorized depending on whether it affects the
exocrine or endocrine functions of the pancreas. There is an important
distinction between the two broad types of pancreatic cancer because they have
different risk factors, causes, symptoms, diagnostic tests, treatments, and
prognoses.
Tumors that affect the exocrine functions are the most common type of
pancreatic cancer. Sometimes these tumors or cysts are benign, called
cystadenomas. However, it is more likely to find malignant tumors called
adenocarcinomas, which account for 95% of exocrine pancreatic cancers.
Adenocarcinomas typically start in gland cells in the ducts of the pancreas,
but they can also arise from pancreatic enzyme cells (acinar cell carcinoma).
Other types of pancreatic cancers that are associated with exocrine
functions include adenosquamous carcinomas, squamous cell carcinomas, and giant
cell carcinomas, named for their appearances underneath a microscope. There is
also a disease called ampullary cancer (carcinoma of the ampulla of Vater) that
starts where the bile duct and pancreatic duct meet the duodenum of the small
intestine.