Women with an average risk of ovarian cancer should not undergo routine screening for the disease, according to a recommendation from the U.S. Preventive Services Task Force.
Reaffirming its original position adopted in 2004, and reiterated in a draft statement released in April, the task force found no new evidence to support a change in the recommendation. In fact, the available evidence suggests that routine screening could do more harm than good.
"The USPSTF found adequate evidence that annual screening with transvaginal ultrasonography and testing for the serum tumor marker cancer antigen (CA)-125 in women does not reduce the number of deaths from ovarian cancer," USPSTF chair Dr. Virginia Moyer of Baylor College of Medicine in Houston, and coauthors wrote in a statement published online in Annals of Internal Medicine.
"There is adequate evidence that screening for ovarian cancer can lead to important harms, including major surgical interventions in women who do not have cancer," they added. "The USPSTF concludes that there is at least moderate certainty that the harms of screening for ovarian cancer outweigh the benefits."
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The task force emphasized that the recommendation applies only to asymptomatic woman. Additionally, the recommendation does not cover women with known risk factors for ovarian cancer, such as BRCA mutations, Lynch syndrome, or a family history of ovarian cancer.
In recommending against routine screening of asymptomatic women, the USPSTF cited results of the NIH-sponsored Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, which showed that screening with CA-125 and transvaginal ultrasound did not reduce a woman's risk of death from ovarian cancer, as compared with unscreened women.
The PLCO results showed that screening with CA-125 and transvaginal ultrasound had a positive predictive value for ovarian cancer of only 1 percent. Additionally, 10 percent of women in the screened arm had false-positive results, which led to oophorectomy in a third of cases. Overall, screened women had a 20:1 ratio of surgeries to screen-detected cancers.
In surgeries triggered by false-positive screening results, the rate of major complications was 21 per 100 surgical procedures.
A Japanese study showed a similar lack of accuracy for screening with transvaginal or transabdominal ultrasound plus CA-125 testing. Investigators in the screening study estimated that 33 surgeries occurred for every case of screen-detected ovarian cancer.
The USPSTF also reviewed preliminary data from an ongoing study of ovarian cancer screening in the U.K. The screening protocol consists of annual CA-125 testing, and transvaginal ultrasound is reserved for women who have abnormal results. Investigators in the trial have developed risk algorithm that takes into account patient age, CA-125 level, and CA-125 trajectory over time.
In the pilot phase of the study, 20 percent of screened women had results suggesting an intermediate risk of ovarian cancer. The women subsequently had as many as five additional screening tests before they were reclassified as low risk.
Fewer than 1 percent of women in the English study had surgery because of abnormal test results (versus 2 percent in the PLCO trial), but surgery showed no evidence of ovarian cancer in 70 percent of cases.
In the ongoing phase of the trial, 9 percent of women have required repeat testing for abnormal results. As in the pilot phase, fewer than 1 percent of women had surgery to investigate abnormal results. Nonetheless, false-positive results were the trigger for surgery in 47 of 97 (48 percent) cases, leading to major complications in 4 percent of cases.
"The USPSTF concludes that there is adequate evidence that there is no mortality benefit to routine screening for ovarian cancer with transvaginal ultrasonography or single-threshold serum CA-125 testing, and that the harms of such screening are at least moderate," the panel wrote.
"Final results from [the British study] should provide more information about the relative benefits and harms of an algorithm-based approach to screening for ovarian cancer."
The panel noted that the recommendation is consistent with those of other major medical organizations -- including the American Cancer Society and American Congress of Obstetricians and Gynecologists -- which have recommended against routine screening for ovarian cancer in asymptomatic women.
The complete statement is available online.