Use of CA125 in Screening for Ovarian Cancer

Use of CA125 in Screening for Ovarian Cancer

June 2010

Results of a multicenter screening trial using calculated algorithms based on age and trends in CA125 levels over time in women without familial risk of developing ovarian cancer have recently been reported at the annual meeting of the American Society of Clinical Oncology. Transvaginal ultrasound (TVUS) was not performed automatically but as indicated by the CA125 algorithm results. This study provides early evidence that incorporating a CA125 algorithm followed by TVUS may be a feasible strategy for screening low-risk women over 50 years of age. The results of this study have been featured in various professional and consumer media outlets, causing physicians and patients to seek guidance regarding the implications.

The Society of Gynecologic Oncology (SGO) commends the investigators of this study for contributing valuable data, and eagerly awaits the results of additional larger randomized controlled trials to confirm the usefulness of Risk of Ovarian Cancer Algorithm (ROCA) in screening women without familial risk of ovarian cancer. The positive predictive value noted in the study of 37.5% is superior to what has been reported from prior studies. However, as a screening strategy, that eventually could be applied to the general population, this figure is modest. There remains insufficient evidence to support routine CA125 +/- TVUS screening in low-risk women who are not part of a clinical trial. An additional limitation of this study was the lack of a control, observation-only arm, without which it is difficult to attribute any real benefit to the screening strategy. As with any prospective screening tool or treatment option, the impact of false positive and false negative screening results must be considered and balanced against the potential benefits of true positive and negative results. Finally, while the number of participants who needed more frequent CA125 monitoring, ultrasound, or referral to a specialist appeared small, a complete cost effectiveness analysis of this approach would be critical before adopting any universal screening program.

As specialists in women’s cancer care, gynecologic oncologists offer patients individualized treatment plans. Patients and their physicians are encouraged to discuss the pros and cons of CA125 and TVUS screening and the implications for subsequent treatment and quality of life.