Pancreatic cancer happens when cells in the pancreas begin to grow out of control. These cancer cells then have the ability to spread to nearby lymph nodes and organs (such as the liver and lungs). When cancer spreads, it is called metastatic. About seventy percent of pancreatic cancers occur in the head of the pancreas, and most of these begin in the ducts that carry the enzymes.
How is Pancreatic Cancer Diagnosed and Staged?
When a physician suspects that a patient may have pancreatic cancer there are several tests that can be done to make a diagnosis. A high quality CT Scan (called a spiral or helical CT) can detect a tumor in the pancreas, enlarged lymph nodes (which may indicate tumor involvement), tumors in the liver, or obstructions of the bile duct. It is the test most commonly used to diagnose this cancer in the United States. Ultrasound can also be used and is the more commonly used test in other areas of the world. Ultrasound uses a device that emits sound waves, which bounce off the organs, producing echoes that are used to create an image of the organ. This can be done on the outside of the abdomen (called transabdominal ultrasound) or from inside the bowel (a catheter is passed through the mouth down to the bowel), this is called endoscopic ultrasound.
If a patient has jaundice, the doctor may want to do a test to find out where the bile duct is blocked and if this blockage is caused by a tumor or another condition. Tests that can determine this are endoscopic retrograde cholangiopancreatography (ERCP) and percutaneous transhepatic cholangiography (PTC). In ERCP, a tube is passed through the mouth down the throat to the bowel, where a small catheter is inserted into the bile and pancreatic ducts. Dye is injected and x-rays are taken. The x-rays will show where the blockage is and what it is caused by. In PTC, dye is injected through a needle that is inserted through the skin, into the liver. The dye moves into the bile ducts, again allowing the blockage and its cause to be seen with an x-ray. In some cases, a small sample of tissue (biopsy) may be removed during these procedures to be examined by a pathologist.
Some patients with pancreatic cancer may have an elevated level of carbohydrate antigen 19-9 (CA 19-9), but this is not present in all cases and may be caused by other things. In patients who have an elevated level, it is useful in confirming a diagnosis in conjunction with other tests and for monitoring the disease during treatment. The level can be periodically checked during treatment to see if the cancer is stable or worsening.
When the physicians talk about staging, they are referring to determining the size of the tumor and if it has spread or not. This information is then used to determine the best treatment. In the case of pancreatic cancer, the size of the tumor and if it involves important blood vessels determines if it can be surgically removed. Pancreatic cancer is staged on the TNM system (also called tumor - node - metastasis system). This describes the size of the tumor (T), if the lymph nodes are involved (N), and if it has spread to other areas of the body (M).