Each year, about 20,000 U.S. women learn they have ovarian cancer.

It accounts for about three percent of all cancers in women and is the fifth leading cause of cancer death. Early diagnosis generally does result in good outcomes. Unfortunately, most cases of ovarian cancer are already advanced by the time they are diagnosed.

There are two current screening tests for ovarian cancer: transvaginal ultrasound and a blood test that measures CA-125, a cancer antigen. Above normal amounts of CA-125 is a sign of ovarian cancer, although cancer is not the only cause of elevated CA-125 levels.

Why ovarian cancer screens may not help women—and may even harm them

The U.S. Preventive Task Force (USPTF) ruled that screening women who are not at high risk for ovarian cancer is potentially harmful and even recommends against it. That's because ovarian cancer screening often produces a false positive. This means the screening test suggests cancer is present when it is not. In order to confirm the diagnosis, women must undergo surgery, which may lead to the removal of healthy ovaries. Surgery itself also has the potential to cause harm.

Perhaps the strongest evidence against ovarian cancer screening comes from the PLOC trial (Prostate, Lung, Colorectal, and Ovarian Cancer Screening Randomized Control Trial), a 13-year study that compared the mortality difference between women who were screened for ovarian cancer and a control group who were not screened. In a video discussing the study, Sandra Fryhofer, MD, said, "The difference in survival between the two groups was not statistically significant. Furthermore, the women in the screened group were subjected to more medical interventions, more oophorectomies [surgical removal of the ovaries], and 20 percent of these women had surgical complications."

Despite the strong evidence and recommendations against screening and the increased risk of harm, Maurie Markman, MD, from the Cancer Centers of America, described a study that found more than 25 percent of the 3,200 physicians surveyed said they don't follow the recommended guidelines for ovarian cancer screening.

The news is not all grim. According to the National Cancer Institute, mortality rates from ovarian cancer declined almost 2 percent per year between 2004 and 2008. Furthermore, researchers are evaluating other potential screening tools, so someday we may have an effective—and safe—way to detect ovarian cancer early.

Jill Maura Rabin, MD, reviewed this article.

 

 

Sources:

U.S. Preventive Services Task Force. "Screening for Ovarian Cancer." Web. September 2012.
http://www.uspreventiveservicestaskforce.org/uspstf12/ovarian/ovarcancerrs.htm

Centers for Disease Control. "Ovarian Cancer." Web. 30 May 2012. http://www.cdc.gov/cancer/ovarian/

National Cancer Institute. "Ovarian Cancer Screening (PDQ®)." Web. 26 January 2012.
http://www.cancer.gov/cancertopics/pdq/screening/ovarian/HealthProfessional

Kaunitz, Andrew M., MD. "Can Ovarian Cancer Screening Save Lives?" Medscape Medical News. Web. 8 February 2012. http://www.medscape.com/viewarticle/756749

Markman, Maurie, MD. "Evidence Says No, but Docs Do It Anyway." Medscape Medical News. Web. 8 March 2012. http://www.medscape.com/viewarticle/759682

Fryhofer, Sandra A., MD. "Screening for Ovarian Cancer: Any Survival Benefit?" Medscape Medical News. Web. 10 October 2011. http://www.medscape.com/viewarticle/750817