Is CA-125 A Screening Test?

Last night just before going to bed, one of my girlfriends forwarded me a story about a young woman who had seen a number of doctors and had a series of tests for abdominal bloating. She was eventually diagnosed with cancer which had spread to her abdomen. The exact cell type and tumour origin was not stated in the email, however the email mentioned that the CA-125 test was done and was very positive. The author then proceeded to promote CA-125 as a screening test and encouraged readers to pass this on to other female readers.

After reading this article I decided this blog post should be about the current recommendations regarding the CA-125 test and its role in screening the general population for Ovarian Cancer.

The bottom line is that CA-125 is not recommended as a screening test for the general population to detect Ovarian Cancer.

The US Preventitive Services Task Force website states “There is no existing evidence that any screening test, including CA-125, ultrasound, or pelvic examination, reduces mortality from ovarian cancer. Furthermore, existing evidence that screening can detect early-stage ovarian cancer is insufficient to indicate that this earlier diagnosis will reduce mortality.”

Why? One of the reasons is, CA-125 can be positive in a variety of other medical conditions and therefore is not suitable as a screening test.
A number of benign conditions can elevate the CA 125 level. For example endometriosis, uterine fibroids (benign tumors), pregnancy, pancreatitis, normal menstruation, pelvic inflammatory disease and liver disease. Benign tumors or ovarian cysts can also cause an abnormal test result. Other cancers can cause an abnormally elevated CA 125, such as cancer of the endometrium, lung, breast, pancreas and gastrointestinal tract.

Another reason. No clinical trials for screening for ovarian cancer in the general population have been completed. There are 3 currently underway; the UK Collaborative Trial of Ovarian Cancer Screening; the NIH Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial; and the European Randomized Trial of Ovarian Cancer Screening.

It should be noted that the American Cancer Society (ACS) , American College of Obstetricians and Gynecologists (ACOG) and the Canadian Task Force on Preventive Health Care (CTFPHC) recommend women with a strong family history of Ovarian Cancer be screened with CA-125 and ultrasound.

Another important point to be aware of is that CA-125 can be useful in women who are already diagnosed with Ovarian Cancer and can be used to monitor response to treatment.

Remember, cancer detection and treatment is constantly in evolution. Recommendations change as a result of new studies and research. This is why it is important to stay informed and visit your doctor at regular intervals so that based on your medical and family history, they can provide you with the best management options custotomized for you.