Women who show no symptoms and have no known hereditary risk for ovarian cancer should skip screening for this cancer, a U.S. task force now recommends.
The U.S. Preventive Services Task Force (USPSTF) made the recommendation in “Screening for Ovarian Cancer,” a “statement” published in The Journal of the American Medical Association (JAMA). It updated the group’s previous recommendation for this cancer, released in 2012.
In it, USPSTF notes that the harm from screening for ovarian cancer, which can include unnecessary surgery, outweighs the benefits, and recommends against screening for ovarian cancer in asymptomatic women who are not at high risk of hereditary cancer.
In the U.S., ovarian cancer is diagnosed in 11 out of 100,000 women per year. Despite its low incidence, the disease is the leading cause of death from gynecologic cancer. Approximately 14,000 women die of ovarian cancer there each year.
Frequently, no symptoms are present in the early stages of the disease, and when they do appear, they are usually nonspecific, including abdominal pain or pressure, bloating, constipation, urinary symptoms, back pain, or fatigue. As a result, most women (88 percent) are not diagnosed until later stages.
The USPSTF recognizes a need for new screening strategies that could detect ovarian cancer early, at a stage when outcomes could be improved. This includes more sensitive and specific serologic tests (to detect antibodies in a blood sample), as well as better imaging techniques.
But the predictive value of current tests for is low, leaving many women with a positive screening test result who do not have ovarian cancer.
USPSTF’s recommendation was based on three large studies showing that screening with transvaginal ultrasound, testing for the serum tumor marker cancer antigen 125 (CA-125), or a combination of both does not reduce ovarian cancer mortality in asymptomatic women who are not considered high risk.
The largest and most recent trial, the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS) (NCT00058032), randomized 202,638 postmenopausal women between ages 50 to 74 to receive either annual screening for seven years or no screening at all.
After a median follow-up of 11.1 years, the mortality rate due to ovarian cancer was 0.32 percent for those receiving CA-125 assessments or transvaginal ultrasound, compared with 0.35 percent of subjects receiving no screening.
In a second study, a pilot trial for the UKCTOCS trial called UK Pilot, 21,955 participants were randomized to receive either three annual CA-125 measurements or no screening. Screened participants with a CA-125 above a certain threshold would be referred for a pelvic ultrasonography.
Again, study results showed no significant difference in deaths from ovarian cancer between the groups.
The third study, called PLCO (NCT01696994), was the only trial conducted in the U.S. It randomized 68,557 women to receive either annual screening with both CA-125 testing and transvaginal ultrasound, or usual care.
After a median follow-up of 12.4 years, 0.34 percent of those in the screening group had died from ovarian cancer, compared with 0.29 percent in the control arm.
While women in the screening groups were not less likely to die from ovarian cancer, they were exposed to considerable stress from false positives, the USPSTF statement says. In the UKCTOCS trial, 11.9 percent of women screened in the first round had a positive result without having the disease.
After the 11 screening rounds from the trial, 44.2 percent of women had a positive CA-125 result at some point but did not have ovarian cancer.
Some women underwent surgery to investigate these positive results, and up to 15 percent of them had major surgical complications.
The USPSTF found that screening for ovarian cancer can result in significant harm, including false positive results that can lead to unnecessary diagnostic surgery.
This recommendation does not apply to women with a family history of ovarian cancer — considered “high risk.” Rather, USPSTF recommends that women with a family history of a disease-causing gene mutation (BRCA1 or BRCA2) should receive genetic counseling and, if indicated, undergo genetic testing.
Responding to concerns from the public about possible risks due to late detection of ovarian cancer, the task force “agrees that screening tests are needed that can accurately detect ovarian cancer earlier to prevent deaths from ovarian cancer.” But tests able to do so accurately and safely do not now exist, it said.
Instead, it concluded, “the evidence shows that currently available tests are not able to do so and can lead to harm by causing healthy women to undergo surgical removal of their ovaries when no cancer is present.”