Why is a CA-125 a poor screening test?
At one time the CA-125 tumor marker created quite a buzz in medical circles, because it was thought to have great potential for becoming a screening test for ovarian cancer. However, several large studies have since revealed that a CA-125 test fails miserably as a screening tool. The CA-125 test fails on most of these counts because: 1.) It is not very sensitive. The CA-125 level is only elevated in 50% of ovarian cancers, and many times it doesn’t become elevated until the cancer has already spread. Therefore, a negative test does not necessarily mean that you are free from ovarian cancer. 2.) It is also very non-specific, especially in pre-menopausal women. The CA-125 level is often elevated during normal menses, endometriosis, pregnancy and fibroids. In addition, it can also be elevated in pancreatitis, appendicitis and other cancers such as breast, lung and colon cancer. Thus, an elevated level can mean many things or literally nothing at all. 3.) The CA-125 test has a high rate of
