2-stage screening promising for ovarian cancer

A screening protocol that takes into consideration CA-125 levels over time and results of transvaginal ultrasound (TVS) shows promise in early detection of ovarian cancer, according to a new report from investigators at the University of Texas MD Anderson Cancer Center.  In a large, prospective study, the combination demonstrated excellent specificity and positive predictive value (PPV) in a group of women at average risk of ovarian cancer.

Published in Cancer, the 11-year study enrolled 4,051 women from 7 sites across the country. None had strong family histories of breast or ovarian cancer and all were healthy, postmenopausal and, aged 50 to 74. The primary endpoint was specificity and the investigators also assessed PPV.

At study entry, each participant underwent CA-125 testing. Based on age and CA-125 score, the women were stratified into one of 3 risk groups: annual CA-125 testing (low risk), repeat CA-125 testing in 3 months (intermediate risk) or TVS and referral to a gynecologic oncologist (high risk). The average rate of referral to a CA-125 test in 3 months was 5.8%; for annual referral to TVS and review by a gynecologic oncologist it was 0.9%.

On the basis of TVS, 10 women underwent surgery, 4 of whom were found to have invasive ovarian cancers (1 stage IA, 2 stage IC, and 1 stage IIB disease), 2 of whom had ovarian tumors of low malignant potential (both stage IA), 1 of whom had endometrial cancer (stage I), and 3 of whom benign ovarian tumors.  For detection of invasive ovarian cancer, the resulting PPV was 40% (95% confidence interval [CI] = 12.2%, 73.8%) and specificity was 99.9% (CI = 99.7%, 100%). Prior to having rising CA-125 levels, all 4 women with invasive ovarian cancer were enrolled in the study for at least 3 years.

Of great importance, the investigators said, was detection of 4 invasive ovarian cancers at an early stage when disease is not only treatable but most often curable. They noted, however, that the findings are neither definitive nor immediately practice-changing. Results of a large, randomized prospective trial-such as a study ongoing in the United Kingdom that is expected to conclude in 2015-are needed to establish the screening protocol’s value.

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