In a study of postmenopausal women at average-risk of ovarian cancer, promising results were obtained with an ovarian cancer screening strategy that combined information about trends in CA-125 blood test results and age, followed as needed by transvaginal ultrasound and referral to a gynecologic oncologist. These results will be presented at the 2010 annual meeting of the American Society of Clinical Oncology (ASCO).
Roughly 70% of ovarian cancers are diagnosed at an advanced stage, highlighting the importance of developing an ovarian cancer screening strategy that accurately identifies cancer at an early, more-treatable stage.
There are currently no ovarian cancer screening tests that are routinely used in women at average-risk of the disease. Potential screening tests such as the CA-125 blood test or transvaginal ultrasound have limited accuracy and have not been shown to reduce the risk of death from ovarian cancer. Levels of the CA-125 protein tend to increase in the bloodstream during ovarian cancer development but can also rise as a result of other conditions.
The ovarian cancer screening strategy that will be presented at the ASCO meeting is called ROCA (Risk of Ovarian Cancer Algorithm). It uses a mathematical model to combine information about patient age and changes in CA-125 levels over time. Based on the results, women are placed in one of three categories:
- Low-risk (repeat CA-125 test in one year)
- Intermediate-risk (repeat CA-125 test in three months)
- High-risk (transvaginal ultrasound and referral to a gynecologic oncologist; based on clinical findings and ultrasound result, the gynecologic oncologist decides whether to proceed to surgery)
This screening strategy was evaluated in 3,238 postmenopausal women between the ages of 50 and 74. Study participants had no significant history of breast or ovarian cancer and were followed for up to eight years.
- Each year less than 1% of women required a transvaginal ultrasound.
- Over the course of the study, a total of 85 women (2.6%) received transvaginal ultrasound and a referral to a gynecologic oncologist.
- Eight women underwent surgery. Three had invasive but early-stage ovarian cancer, two had borderline ovarian tumors, and three had benign ovarian tumors.
Overall, the screening strategy was feasible, had a low rate of false-positive results, and was able to identify some women with early ovarian cancer.
A large-scale study of ROCA is underway in the United Kingdom, with results expected in 2015.
Reference: Lu KH, Skates S, Bevers TB et al. A prospective U.S. ovarian cancer screening study using the risk of ovarian cancer algorithm (ROCA). To be presented at the 2010 annual meeting of the American Society of Clinical Oncology. June 4-8, 2010. Chicago, IL. Abstract 5003.