NCI study examines outcomes from surgery to prevent ovarian cancer

A new study looked at women at high risk of ovarian cancer who had no clinical signs of the disease and who underwent risk-reducing salpingo-oophorectomy (RRSO). The study results showed cancer in the removed tissues of 2.6 percent (25 of 966) of the participants. RRSO is a surgical procedure in which a woman’s ovaries and fallopian tubes are preventively removed. The participants included women known to carry a harmful mutation in the BRCA1 gene or the BRCA2 gene, as well as women considered at high risk because of a strong family history of the disease. Cancer was detected in tissues from 4.6 percent of the women who carried a BRCA1 mutation, 3.5 percent of those with a BRCA2 mutation and 0.5 percent of women who had a family history but did not carry a BRCA1 or BRCA2 mutation. The researchers also found that some of these cancers arose in the fallopian tubes, a result that supports emerging evidence that many malignancies classified as ovarian cancer actually arise in the fallopian tubes. This underscores the importance of fallopian tube removal as part of risk-reducing surgery. These cancer risk estimates provide the best available information for high-risk women considering RRSO.

The study, led by Mark H. Greene, M.D., senior investigator, Clinical Genetics Branch, Division of Cancer Epidemiology, and colleagues from DCEG and the Division of Cancer Prevention, was published in the Journal of Clinical Oncology, September 8, 2014. The participants included asymptomatic high-risk women 30 years of age or older. Before surgery, the women provided risk factor information and underwent a blood test for ovarian cancer (CA-125 antigen) and a trans-vaginal ultrasound. (These screening tests are currently considered the standard of care for high-risk women, but not for the general population.) The investigators found that having a BRCA1 or BRCA2 mutation, being postmenopausal, having a high preoperative CA-125 blood level, or having an abnormal trans-vaginal ultrasound result increased the likelihood that cancer would be detected. No cancers were detected among the high-risk mutation-negative women who had normal preoperative CA-125 blood levels and trans-vaginal ultrasound results. More than half of the cancers detected via RRSO were early stage (stage 0, I or II), compared with only about 15 percent of ovarian cancers detected in the general population. Although RSSO reduces cancer risk and improves survival in mutation carriers, it causes infertility and premature menopause, which makes electing for surgery a difficult decision. These new findings may help high-risk women select the treatment plan that is best for them.