Objective: To evaluate positive predictive values of CA 125 or transvaginal ultrasonography screening for ovarian cancer according to family history of breast or ovarian cancer.
Methods: In the screening arm of a randomized controlled trial of screening compared with usual care, 28,460 women with family history data received baseline and annual CA 125 and transvaginal ultrasonography examinations. We analyzed CA 125 and transvaginal ultrasonography results from the first four rounds of screening. We classified women as average (n=22,687), moderate (n=2,572), or high (n=2,163) risk based on family history, or high risk due to a personal history of breast cancer (n=1,038). Cancers were identified by active follow-up of women with abnormal screening results and annual questionnaires. We calculated positive predictive values for screening combinations.
Results: Similar proportions (4.8-5.0%) of women in each group had abnormal screening results. Higher-risk women were more likely than lower-risk women to undergo biopsy after a positive screen. Screening identified 43 invasive ovarian cancers. The positive predictive values for abnormal screening results were 0.7% in average-risk, 1.3% in moderate-risk, and 1.6% in high-risk groups; one ovarian cancer occurred among the breast cancer survivors. The positive predictive values for postbaseline abnormal screening results were also higher in the higher-risk groups. The positive predictive values did not significantly differ across risk groups.
Conclusion: Probabilities of abnormal annual CA 125 and transvaginal ultrasonography screens were similar across groups based on family history of breast or ovarian cancer. However, ovarian cancer was more likely to be diagnosed after an abnormal screening result among women at higher family history-based risk than among women at lower risk.
Level of evidence: I.
Trial registration: ClinicalTrials.gov NCT00002540.