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The pancreas is an organ of the digestive system located deep in the upper part of the abdomen, behind the stomach and in front of the spine.
It is only about 2 inches wide and 6 to 8 inches long and sits horizontally
across the abdomen.The pancreas is composed of three parts.
The endocrine glandular tissue of the pancreas produces hormones and
releases them into the bloodstream. The hormones are made in collections
of cells called the Islets of Langerhans, which are found in small clusters
throughout the pancreas. Insulinis an important hormone made in these
cells and helps control blood sugar levels.
The word cancer is used to describe any one of a group of diseases in which the cells are abnormal, grow out of control, and can spread. These abnormal cells are different from normal cells in both appearance and function.
Pancreatic cancer occurs when abnormal cells grow out of control in the
tissue of the pancreas and form a tumor
Because the pancreas lies deep in the abdomen, a doctor performing an
examination on a patient would not be able to feel a pancreatic tumor.
Pancreatic cancer has no early warning signs, and there are no effective
screening tests. As a result, pancreatic cancer rarely is discovered early.
Many times the diagnosis is not made until the cancer has spread to other
areas of the body.
In the United States, pancreatic cancer is the fourth leading cause of
cancer deaths in both men and women. In2007, about 37,000 patients
will be diagnosed with pancreatic cancer. Almost all patients with
pancreatic cancer are older than 55 years (90 percent), and more than
70 percent are older than 65 years. Unfortunately, pancreatic cancer can
also occur in younger people, especially those who have a family history
of the disease. Today, better diagnostic tests and newer treatments are
beginning to change these statistics and provide a moreoptimistic future
for patients diagnosed with pancreatic cancer.
The most common types of pancreatic cancers areexocrine tumors called
ductal adenocarcinomas, which are thought to form in the pancreatic
ducts. About two thirds of all pancreatic cancers form in the head of the
pancreas. The other third form in the body and tail.3These tumors are
malignant, meaning they can invade nearbytissues and organs. Cancerous
cells can also spread through the blood and lymphatic systemto other
parts of the body. When this occurs, it is called metastaticcancer and it
may be life-threatening.
Tumors can also form in the endocrine cells of the pancreas. These types of rare tumors are called islet cell tumors or pancreatic endocrine neoplasms, and most often they are benign.Those that are malignant are called islet cell cancers or malignant pancreatic endocrine neoplasms. Other rare forms of pancreatic cancer are listed in Box 1-1. It is important to distinguish between exocrine and endocrine tumors because each has different signs and symptoms, are diagnosed using different tests, have different treatments, and have different prognoses. This handbook does not focus on endocrine tumors or other rare tumors of the pancreas and related organs. However, most National Cancer Institute–Designated Comprehensive Cancer Centers have experts who can help patients who have these rare pancreatic tumors.
Until recently, little was known about pancreatic cancer. Because of
new discoveries in all types of cancer, more research is being focused on
pancreatic cancer. Scientists are beginning to understand the genetic basis
of this disease. (See Section 2 on Causes.)This knowledge may help in
understanding its causes and in determining who is most at risk.Eventually, new and better ways to treat pancreatic cancer will be discovered.
Intraductal papillary mucinous neoplasms (IPMNs)have been recognized
as a special type of abnormal tumors in the pancreas. These tumors are
called “mucinous” because they produce large amounts of mucus, which
clogs and enlarges the pancreatic duct. IPMNs are very different from most
pancreatic tumors. They may be present for a long time without spreading,
and patients with some types of IPMNs have a good chance of a cure with
surgery. Because IPMNs also have very distinct features, researchers believe that studying them and their genetic makeup may lead to new ways of diagnosing moretypical forms of pancreatic cancer
Pancreatic intraepithelial neoplasia (PanIN) are lesions too small to see with the naked eye. Like IPMNs, PanIN lesions can also progress to invasive pancreatic cancer over time.
RARE FORMS OF PANCREATIC CANCER
Endocrine tumors
- Gastrinomas
- Glucagonomas
- Insulinomas
- Somatostatinomas
- VIPomas
Cystic tumors
- Mucinous cystic neoplasms
- Serous cystic neoplasms
- Solid pseudopapillary tumors
- Cystic islet cell tumors
- Intraductal papillary mucinous neoplasms (IPMNs)
Acinar cell cancer
Variants of ductal adenocarcinoma, such as
- Adenosquamous carcinoma
- Colloid carcinoma
- Hepatoid carcinoma
- Medullarycarcinoma
- Signet ring cell carcinoma
- Undifferentiated carcinoma
Pancreatic lymphoma
Metastases to the pancreas from a cancer arising in another organ
» Learn about the Causes of Pancreatic Cancer
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