No major medical organizations recommend routine ovarian cancer screening, but that hasn't stopped doctors from regularly testing for the disease. According to a new study, primary care physicians and OB-GYNs regularly screen women at low-risk for ovarian cancer, exposing them to "substantial" potential harms.
In the paper, published Monday in the Annals of Internal Medicine, researchers analyzed survey responses from doctors who were asked whether they would "almost always," "sometimes" or "almost never" order -- or offer -- ovarian cancer screening during a woman's annual exam. The researchers changed the hypothetical patient's age, race and insurance, as well as her genetic and hereditary risk factors for ovarian cancer -- a disease often called the "silent killer" because it goes undetected until it has spread.
From a final pool of more than 1,000 physicians, some six percent of respondents said they routinely ordered or offered ovarian cancer screening for low-risk women, while nearly a quarter said they regularly offered it to medium-risk women.
To put that in perspective the researchers estimate that, if applied nationally, approximately 1.2 million women in the U.S. would be at risk for undergoing ovarian cancer screening tests -- tests that are potentially harmful.
"We're encouraged that providers are thinking about ovarian cancer as they see their patients; however, we’re concerned by the results of this study, which indicate that providers may be over-testing women for ovarian cancer," said Cara Tenenbaum, vice president for policy and external affairs with the Ovarian Cancer National Alliance, who was not associated with the study.
"Invasive surgery is one potential outcome from these tests; another is the thought that we've checked the box on ovarian cancer, and no longer need to worry about it, despite symptoms or risk factors," she continued.
The U.S. Preventive Services Task Force, one of the nation's key government health panels, recommends against routine screening for the disease, saying that there is a relatively low incidence of ovarian cancer in the general population as a woman's lifetime risk of developing the disease is 1 in 71. There is, however, high risk of false positives with the current tests.
Currently, the leading tests for ovarian cancer are the transvaginal ultrasound [TVU], in which doctors insert a probe into a woman's vagina to examine her ovaries, and a blood test looking for CA 125, a protein that can be present in abnormally high levels among women with ovarian cancer.
But results from the large Prostate, Lung, Colorectal and Ovarian Cancer Screening trial published last year found that 8 percent of women who underwent regular blood tests and ultrasounds had false positives, and nearly a third of them underwent unnecessary surgery. A small percentage had serious complications.
All of which begs the question: Why do doctors regularly ignore the fact that no major medical organization currently recommends regular screening?
According to the study's authors, many simply overestimate a woman's ovarian cancer risk in the first place, and groups like the American Cancer Society do state that women with a strong family history "may be screened." The authors also suggest that doctors may be more inclined to order tests for patients who request them.
But perhaps more fundamental to the doctors' decision to screen is the study's finding that one in three indicated a belief that the current testing options are effective.
"I do not understand why a third of the physicians believe [transvaginal ultrasound] or CA 125 are effective screening tests for ovarian cancer, since there is evidence to the contrary and no organization recommends these tests for screening," Dr. Laura-Mae Baldwin, a member of the department of family medicine at the University of Washington and one of the study's authors, told The Huffington Post.
Of course, guidelines from groups like the USPTF apply to the population at large. High-risk women with a strong family history of the disease or certain gene mutations may want to consider testing.
"Women at high risk of developing ovarian cancer should consult with their doctors about a monitoring protocol or preventive surgery," Tenenbaum said, calling out what she identified as a pressing need for research into better screening options.
For the general population -- at relatively low risk for the disease -- pelvic examinations may be the best screening option currently available to us, experts say.
"That's really what you need to do," said Dr. Rebecca Liu, a gynecologic oncologist with the University of Michigan Medical School who cautioned that the symptoms of ovarian cancer are often ignored. "We can't do this out of fear until we find something better."