How is Pancreatic Cancer Diagnosed?
There are three main ways to diagnose cancer: Imaging Tests, Blood Tests, and Biopsy.
I. IMAGING TESTS
The most important tests used to detect pancreatic cancer are imaging tests. These tests use a variety of methods to see inside the body. Imaging tests can be simple X-rays or more complex scanning methods that use computers to reconstruct the structures in the body. Some typical imaging tests are described in this section, and their uses are listed in the Table below.
II. BLOOD TESTS
Blood tests are frequently performed for diagnostic purposes. No single blood test can be used to make a diagnosis of pancreatic cancer. When a person has pancreatic cancer, however, elevated levels of bilirubin or liver enzymes may be present.
Different tumor markers in the blood are used to detect and monitor many types of cancer. Tumor markers are substances, usually complex proteins, produced by tumor cells. Proteins form the basis of body structures such as cells, tissues, and organs. Enzymes and some hormones are composed of protein. Some tumor markers can indicate specific types of cancer; others are found in several types of cancer.
Two commercially available tumor marker tests are of use in patients with pancreatic cancer, cancer antigen 19-9 (CA 19-9) and carcinoembryonic antigen (CEA). These markers are not accurate enough to be used to screen healthy people for or to make a diagnosis of pancreatic cancer. However, CA 19-9 and CEA are frequently used to track the progress of treatment in patients with pancreatic cancer. CA 19-9 is a protein found on the surface of certain types of cells and is shed by tumor cells, making it useful in following the course of cancer. The presence of the protein CEA may indicate cancer because elevations in CEA levels are not usually found in people who are healthy. CEA is not as useful as is CA 19-9 in pancreatic cancer testing.
Because the only definitive way to diagnose cancer is to directly visualize cancer cells under a microscope, a biopsy may be performed when pancreatic cancer is suspected. Although typically needed for patients who have undergone an initial round of chemotherapy or radiation therapy, not every pancreatic mass needs to be biopsied. A biopsy is the process of removing tissue samples, which are then examined under a microscope to check for cancer cells.