On July 18, the U.S. Preventive Services Task Force (USPSTF) released a draft recommendation statement(www.uspreventiveservicestaskforce.org) and draft evidence review(www.uspreventiveservicestaskforce.org) assessing the benefits and harms of screening ovarian cancer. Based on its review of the evidence, the task force reiterated its 2012 final recommendation that the potential harms of screening outweigh the benefits, and women who are asymptomatic should not be screened -- a "D" recommendation(www.uspreventiveservicestaskforce.org).
"The task force found that screening women without signs or symptoms for ovarian cancer does not decrease the number of deaths from the disease and may lead to unnecessary surgeries," said USPSTF member Maureen Phipps, M.D., M.P.H., in a news release(www.uspreventiveservicestaskforce.org). "Therefore, the task force recommends against screening for ovarian cancer in women who have no signs or symptoms and who are not at high risk for ovarian cancer."
It's important to note that this draft recommendation doesn't apply to women who are at high risk for ovarian cancer, such as women known to have certain BRCA1 or BRCA2 genetic mutations. The task force has a separate recommendation(www.uspreventiveservicestaskforce.org) on risk assessment and genetic counseling and testing for BRCA-related cancer, which is currently being updated.
- The U.S. Preventive Services Task Force has released a draft recommendation statement reaffirming that potential harms of screening for ovarian cancer outweigh the benefits, and asymptomatic women shouldn't be screened.
- This draft recommendation doesn't apply to women who are at high risk for ovarian cancer, such as women known to have certain BRCA1 or BRCA2 genetic mutations.
- The task force is inviting comments on its draft recommendation statement and draft evidence review until 8 p.m. EDT on Aug. 14.
The USPSTF commissioned an updated review of the evidence on ovarian cancer screening that evaluated the benefits and harms of screening in asymptomatic, average-risk women. Outcomes of interest included ovarian cancer mortality, quality of life, false-positive test result rates, surgery and surgical complication rates, and psychological effects of screening. Any screening approach that was evaluated in clinical trials reviewed was included.
The task force identified three good-quality studies that examined how annual screening affected asymptomatic women not at high risk for ovarian cancer, and none of them found that screening significantly reduced ovarian cancer mortality.
The largest and most recent trial, the United Kingdom Collaborative Trial of Ovarian Cancer Screening (UKCTOCS), was a randomized, controlled trial involving 202,638 postmenopausal women ages 50-74. The trial evaluated screening using one of two methods -- transvaginal ultrasound or CA-125 testing with the risk of ovarian cancer algorithm (ROCA), which assesses changes in CA-125 values over time -- after a baseline age-adjusted measurement.
Women randomized to the transvaginal ultrasound arm, as well as those randomized to the CA-125 ROCA arm, received annual testing. Participants found to be at increased risk for ovarian cancer based on their ROCA score were then screened with transvaginal ultrasound.
After a median follow-up of 11.1 years, ovarian cancer mortality was similar in the control and intervention groups (0.35 percent, 0.32 percent and 0.32 percent in the control, transvaginal ultrasound and CA-125 ROCA groups, respectively).
The pilot trial for UKCTOCS, known as UK Pilot, was much smaller (n=21,955 randomized) and evaluated the use of a single cutpoint value for CA-125 testing, finding no significant difference in ovarian cancer mortality between screened and unscreened women.
The Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial randomized 78,216 U.S. women to either annual screening (CA-125 testing and transvaginal ultrasound for the first four rounds of screening, then CA-125 testing only for an additional two rounds) or usual care. The median follow-up period was 12.4 years. No difference in ovarian cancer mortality was seen among the two groups.
The USPSTF reviewed evidence on harms of screening for ovarian cancer from these and a fourth fair-quality study that reported on quality of life and psychological harms of screening.
False-positive rates calculated for the various screening methods were
- 4.2 percent in the UK Pilot trial (excluding peritoneal cancer);
- 11.9 percent in the UKCTOCS trial in the first round of screening with transvaginal ultrasound (excluding peritoneal cancer);
- 9 percent in the UKCTOCS trial in the first round of screening with CA-125 ROCA (excluding peritoneal cancer);
- 44.2 percent in the UKCTOCS trial in all subsequent rounds of screening with CA-125 ROCA; and
- 9.6 percent in the intervention arm of the PLCO trial.
Across all the trials reviewed, the percentage of women randomized to screening who had surgery because of false-positive test results ranged from 0.2 percent to 3.2 percent. Of this group, 0 percent to 15 percent of participants experienced major surgical complications.
"The current screening tests do not do a good job identifying whether a woman does or does not have ovarian cancer," said USPSTF Chair David Grossman, M.D., M.P.H., in the release. "The task force hopes that in the future, better screening tests for ovarian cancer will be developed."
A Family Physician's Perspective
Jennifer Frost, M.D., medical director for the AAFP Health of the Public and Science Division, told AAFP News the studies reviewed show that screening for ovarian cancer using transvaginal ultrasound and/or CA-125 testing does not reduce mortality from ovarian cancer but is associated with a high false-positive rate.
"This means that a significant number of women undergo further testing, including diagnostic surgery, when they do not have ovarian cancer," she said. "These women are exposed to potential surgical complications and may undergo unnecessary salpingo-oophorectomy."
Frost reiterated that there currently isn't an effective screening strategy for ovarian cancer.
"Many clinicians perform a bimanual pelvic exam for this purpose, but the positive predictive value of the pelvic exam is zero to 3.6 percent," she said.
And although the USPSTF said there is insufficient evidence to recommend against the bimanual exam, the AAFP and the American College of Physicians recommend against this exam given its low positive predictive value and the risk of harms, Frost added.
"Family physicians should remember that these recommendations are for women at average risk," she said. "Although there is not an effective screening strategy for screening women at high risk, some of these women may be appropriate for BRCA testing."
The USPSTF is inviting comments on its draft recommendation statement(www.uspreventiveservicestaskforce.org) and draft evidence review(www.uspreventiveservicestaskforce.org).
The public comment window is open until 8 p.m. EDT on Aug. 14. All comments received will be considered as the task force prepares its final recommendation.
The AAFP will review the USPSTF's draft recommendation statement and supporting evidence and provide comments to the task force. The Academy will release its own recommendation on the topic after the task force finalizes its guidance.
Related AAFP News Coverage
AAFP Recommends Against Pelvic Exams in Asymptomatic Women
Guidance Differs From USPSTF Final Recommendation