Cancer arises when the cells in the body begin to grow uncontrollably. Cells from almost any part of the body can become cancer and can spread to other areas of the body. To learn more about the origin and spread of cancer, read What is cancer?
Pancreatic cancer arises when the cells of the pancreas begin to grow out of control. The pancreas is an organ that lies behind the stomach. Its shape resembles that of a fish, with a broad head, body that goes from wide to thin and a narrow pointed tail. In adults, it measures approximately 6 inches in length and less than 2 inches in width. The head of the pancreas is to the right of the abdomen (belly), behind where the stomach and the duodenum meet (the first part of the small intestine). The body of the pancreas is behind the stomach and the tail of the pancreas is to the left of the abdomen, next to the spleen.
The pancreas has two main types of cells:
Exocrine cells: Most of the cells of the pancreas make up the exocrine glands and the ducts. The exocrine glands produce pancreatic enzymes that are released into the intestine to help you digest food (especially fats). Enzymes are first released in tiny tubes called ducts. These ducts join together to form larger ducts that empty into the pancreatic duct. The pancreatic duct joins with the common bile duct (the conduit that transports bile from the liver), and empties into the duodenum (the first part of the small intestine) at the level of the ampulla of Vater.
Endocrine cells: The endocrine cells make up a much smaller percentage of the cells in the pancreas. These cells are in small clusters called islets (or pancreatic islets of Langerhans). The islets produce important hormones, such as insulin and glucagon (which help control blood sugar levels), and release them directly into the blood.
The exocrine and endocrine cells of the pancreas form tumors of different types. It is very important to distinguish between exocrine and endocrine pancreatic cancer. Each one has different risk factors, as well as different causes, signs and symptoms, they are diagnosed with different tests, they are treated differently and their prognoses differ among themselves.
Exocrine pancreatic cancers.
Exocrine cancers are by far the most common type of pancreatic cancer. If you are told that you have pancreatic cancer, it is more likely to be an exocrine pancreatic cancer.
Pancreatic adenocarcinoma: approximately 95% of exocrine pancreatic cancers are adenocarcinomas. Generally, these cancers originate in the ducts of the pancreas. Less commonly, they are formed from the cells that produce the pancreatic enzymes. In this case they are called acinar cell carcinomas.
Less common types of exocrine cancer: the other less common types of exocrine pancreatic cancer include adenosquamous carcinomas, squamous cell carcinomas, signet ring cell carcinomas, undifferentiated carcinomas, and undifferentiated giant cell carcinomas.
Ampullary cancer (carcinoma of the ampulla of Vater): this cancer originates in the ampulla of Vater, the place where the biliary tract and the pancreatic duct join and end at the small intestine. Ampullary cancers are not technically pancreatic cancers, but they are included in this information because they are treated in very similar ways.
These cancers often clog the bile duct when they are still small and have not spread much. This blockage causes bile to accumulate in the body, which causes the skin and eyes to turn yellow (jaundice). For this reason, these cancers are usually detected earlier than most pancreatic cancers, and usually the prognosis is better.
Signs and symptoms of pancreatic cancer.
The symptoms of pancreatic exocrine cancers and pancreatic neuroendocrine tumors are often different so they are described separately.
Having one or more of the symptoms that are presented below does not mean that you have pancreatic cancer. In fact, many of these symptoms are more likely to be caused by other conditions. However, if you have any of these symptoms, it is important that a doctor examine you so that the cause can be determined and treated if necessary.
Treatment according to the extent of the cancer
The treatment of exocrine pancreatic cancer, the most common type of pancreatic cancer, is different from the treatment of pancreatic neuroendocrine tumors that is discussed in another section.
In most cases, the treatment of pancreatic cancer is based on its stage (how far it has spread in the body). However, other factors, such as your general state of health, may affect treatment options. Check with your doctor if you have any questions about the treatment plan he or she recommends.
It can be difficult to determine the stage of pancreatic cancer accurately by imaging studies. Doctors do their best to determine before treatment whether there is a good chance that the cancer will be resectable (that is, if it can be completely removed). However, sometimes it turns out that cancers have spread more than initially thought.
Treatment of resectable cancer.
In general, surgeons believe that a pancreatic cancer is resectable if it still appears to be inside the pancreas or does not extend far from the pancreas, and has not invaded large adjacent blood vessels. A person must also be healthy enough to tolerate surgery to remove the cancer, which is a complex operation.
If imaging studies show a reasonable likelihood of being able to remove the cancer completely, surgery is the preferred treatment if possible, because it is the only realistic cure opportunity. Depending on where the cancer originated, surgery is usually performed with the Whipple technique (a pancreatoduodenectomy) or a distal pacretectomy.
Sometimes, even when a cancer is thought to be resectable, it is evident during the operation that it is not possible to remove it completely. If this happens, continuing with the operation could cause more harm than good. Surgery may be suspended, or the surgeon may continue with a simpler operation to relieve or prevent problems, such as bile duct obstruction.
Even when the surgeon believes that all cancer has been removed, the cancer may return. Administering chemotherapy (chemo), either alone or with radiation therapy (chemoradiation) after surgery (known as adjuvant treatment) may help some patients live longer. Gemcitabine (Gemzar) or 5-FU are the most commonly used chemotherapy drugs.