A prospective U.S. ovarian cancer screening study using the risk of ovarian cancer algorithm (ROCA).

Abstract

5003 Background: There are currently no effective screening tools for the early detection of ovarian cancer in women at average population risk. We evaluated a screening strategy that incorporates change of CA-125 over time and age of the participant to estimate risk of ovarian cancer, referring a small fraction (∼2%) of apparently healthy individuals annually to transvaginal sonography (TVS). Methods: A single arm, prospective, multicenter screening study enrolled postmenopausal women age 50 to 74 with no significant family history of breast or ovarian cancer. Participants underwent a CA-125 blood test annually. Based on the Risk of Ovarian Cancer Algorithm (ROCA) result, women were triaged to the next annual CA-125 (low risk), repeat CA-125 in 3 months (intermediate risk), or TVS and referral to a gynecologic oncologist (high risk). Based on clinical findings and TVS, the gyn onc made the decision whether to proceed with surgery. Results: 3238 women participated over an eight year period. The average annual rate of referral to 3 monthly CA125 was 6.8%, and the average annual rate of TVS and gyn onc referral was 0.9%. Cumulatively 85 women (2.6%) received TVS and referral to a gyn onc. Eight women subsequently underwent surgery based on the TVS and referral, with 3 invasive ovarian cancers, 2 borderline ovarian tumors and 3 benign ovarian tumors, providing a positive predictive value of 37.5% (95% CI 8.5%,75.5%).The combined specificity of ROCA followed by TVS for referral to surgery is 99.7% (95% CI 99.5%, 99.9%). The 3 invasive ovarian cancers were high-grade epithelial tumors that were all early stage (two stage 1C and stage IIB). All 3 women with invasive ovarian cancer had at least 3 years with low risk, annual CA-125 values prior to a rising CA-125. Conclusions: In this prospective, single arm study, the ROCA followed by TVS demonstrated excellent specificity and PPV in a population of U.S. women at average risk for ovarian cancer. As expected, less than 1% of participants annually required a TVS. In addition, the invasive high-grade ovarian cancers that were detected were early stage. This study provides early evidence that ROCA followed by TVS is a feasible strategy for screening women over 50 years of age. Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Fujiresio Diagnostics Inc Roche Diagnostics Royalties for CA 125