New ovarian cancer screening strategy generates hope

A novel screening strategy for postmenopausal women at average risk of ovarian cancer has been tested with promising results, say researchers at MD Anderson Cancer Center at the University of Texas, US.

This new strategy uses a mathematical model – the Risk of Ovarian Cancer Algorithm (ROCA) – based on analyzing the trend of CA-125 blood test results over time in combination with a woman’s age. The strategy then calls for referral of a small number of women – those with high ROCA scores – to transvaginal ultrasound (TVS) and a gynecologic oncologist, if necessary.

The strategy is important as there is no effective screening tool for early stage ovarian cancer among women at average risk. Currently, almost 75 percent of patients present with advanced stage disease, and the cure rates are less than 30 percent. If detected early, the chances of cure rise to between 60 and 90 percent. And even though CA-125 protein levels increase as ovarian cancer progresses – especially in post-menopausal women – it’s not a perfect marker because it can become elevated in response to other factors as well.

“In this 9-year screening trial of [3,238] postmenopausal women, aged between 50 to 74 years with no significant family history of breast or ovarian cancer, the ROCA followed by TVS demonstrated very few false positives – specificity was [99.7] percent – and fewer than 1 percent of women required a TVS each year,” said Dr. Karen Lu, lead author of the study and professor of gynaecologic oncology at MD Anderson Cancer Center.

Study participants underwent a CA-125 blood test annually and based on the ROCA results, they were triaged to the next annual CA-125 for those at low risk, repeat CA-125 in 3 months for those at intermediate risk, and TVS or referral to a gynecologic oncologist for those at high risk.

“Overall the positive predictive value was 37.5 percent (95% CI 8.5%,75.5%), which means that no more than three operations would be required to detect one invasive ovarian cancer. Eight women underwent surgery based on the ROCA results. Out of these, three had invasive but early-stage ovarian cancer, two had borderline ovarian tumours and three had benign ovarian tumours,” said Lu.

A large-scale ROCA study involving more than 200,000 women is under way in the UK, with results expected in 2015. “We need to await the results of this trial that examines mortality as an endpoint. If the algorithm is validated, CA-125 testing could be recomended as part of a woman’s annual medical check-up,” concluded Lu.

Source: mims.com