Last month, the United States Preventive Services Task Force an group of 16 independent experts who are charged with objectively evaluating evidence regarding medical tests and procedures issued its recommendation against screening healthy women of any age for ovarian cancer.
Their evaluation of numerous studies found that neither of the two common methods of detecting ovarian cancer early a blood test CA-125, and pelvic ultrasound reliably found cancer early enough to save anyone from death, and in fact led to many false positive results and unnecessary procedures as a result.
The largest study reviewed by the panel was published last year in the Journal of the American Medical Association.
In it, among over 78,000 women between the ages of 55 and 74, half were screened and half were not (the screening tests were those mentioned: CA-125 and transvaginal/pelvic ultrasound). Over the course of about ten years, there was no difference in deaths from ovarian cancer between the two groups. There was, however, an important difference: among the women who were screened, almost ten percent had a false positive result. And almost one-third of those had some sort of surgical procedure done, needlessly. The false positives were attributable to benign ovarian cysts or elevated CA-125 caused by other conditions.
These findings and the panel announcement were particularly distressing since cancer of the ovaries is a highly lethal type: While it is not very common, with just under 23,000 new cases last year, it is very difficult to catch early enough: 15,500 deaths are expected this year, according to the American Cancer Society. It must be emphasized, however,that this advisory does not apply to women at higher risk of ovarian cancer: those with a strong family history of the disease, or those with a genetic mutation increasing the risk (such as BRCA-1 or -2).
Despite the study findings and the panel recommendation, some doctors continue to screen women for ovarian cancer anyway. Sometimes, patients request it, clinging to the mistaken belief that the tests can somehow find the disease early enough to save lives. A physician surveyreported in the Annals of Internal Medicine earlier this year, based on responses from over one-thousand doctors, said that about a third of them believed the screening was effective and that many routinely offered it to patients.
The lessons here are twofold: First, doctors fervently desire to find earlier methods to detect potentially lethal cancers, of course and so do their patients. But that should not blind them to the facts: screening for ovarian cancer does more harm than good, in general, and should not be done without good reason. This is hard for some doctors to accept. More importantly, better diagnostic predictors of ovarian cancer need to be developed to avert the lethal consequences of this silent killer.