Women should not undergo routine testing for ovarian cancer, the U.S. Preventive Services Task Force announced this week, reaffirming previous concerns that the tests do more harm than good because of the risks of invasive procedures that follow false positives.
Ovarian cancer has the highest mortality rate of all types of gynecologic cancer and is the fifth-leading cause of cancer deaths among women overall. About 13 out of 100,000 women will develop ovarian cancer. The American Cancer Society reports that 22,280 American women will be diagnosed with the disease this year and 15,500 will die from it. Most deaths occur in women over 55.
In the new issue of the journal Annals of Internal Medicine, the task force reported that it found the "positive predictive value" of routine ovarian cancer screening to be low and that "most women" who test positive will not have the cancer. The panel's report claimed there was "adequate evidence" that annual screening, either through a transvaginal ultrasound or a blood test for the tumor marker known as (CA)–125, "does not reduce the number of ovarian cancer deaths" and can lead to "important harms, including major surgical interventions in women who do not have cancer." The experts concluded that "there is at least moderate certainty that the harms of screening for ovarian cancer outweigh the benefits."
"There is no existing method of screening for ovarian cancer that is effective in reducing deaths," Dr. Virginia Moyer, a pediatrics professor at Houston's Baylor College of Medicine and chair of the task force, said in a statement. (The 16-member panel is appointed by the government but is independent of federal agencies.) "In fact, a high percentage of women who undergo screening experience false-positive test results and consequently may be subjected to unnecessary harms, such as major surgery."
One key study reviewed by the task force analyzed the medical outcomes of more than 78,000 women over 55 and found no difference in death rates from ovarian cancer between those who were screened for the disease and those who weren't. Half the women were not screened; 10 percent of those who were, about 3,300, had false positives. Nearly 1,100 of those women had surgery and 163 experienced at least one serious complication — such as blood clots, injuries or infections — as a result of unnecessary procedures.
False positives are common in ovarian cancer screening because the (CA)-125 marker can be elevated by causes other than cancer, and the ultrasound test alone cannot effectively distinguish between cancer and benign ovarian enlargement or cysts. Other research has indicated that the high rate of false positives is only part of the problem — that, even when accurate, the screening is generally unable to detect ovarian cancer early enough to save women's lives. Ovarian cancer is usually well advanced by the time it is detected, and so even more accurate positive tests from current practices would have little impact on the death rate from the disease.
The task force's advice does not apply to women showing symptoms of ovarian cancer or those who have a family history or a genetic predisposition to developing the disease. Women in those groups should consult with their doctors about testing options. Some possible symptoms of ovarian cancer include persistent bloating, pelvic or abdominal pain, quickly feeling full from eating and a high frequency of urination.
The task force's recommendations have sometimes been controversial, including its recent advice against routine prostate-cancer screening for men. But in the case of ovarian-cancer screening, it is in sync with mainstream medical thinking. Neither the American Cancer Society nor the American Congress of Obstetricians and Gynecologists recommends routine ovarian cancer screening for asymptomatic women who are not at high risk. And yet many physicians continue to perform the tests on women in that category.
“We are fueled by hope,” Moyer told The New York Times. “It’s such a terrible disease. Almost everyone knows somebody who’s had it, and that means somebody who’s died of it. You get the feeling you should do anything possible to avoid that situation, but it’s easy to forget that what you do to avoid it can make matters worse."
Gynecologic oncologist Barbara Goff of the Fred Hutchinson Cancer Research Center in Seattle, who authored a recent study finding that about a third of doctors still favored routine screening, told the Times, "If patients request it, then I think a lot of times physicians feel it's just easier to order the test, particularly if it's covered by insurance, rather than taking the time to explain why it may not be good, that it could lead to inappropriate surgery, could lead to harm. I don't think they think through the consequences."
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