In ovarian cancer, the standard of care for women who are high-risk remains risk-reducing salpingo-oophorectomy (RRSO). There are women who want to postpone this surgery, however, and experts are searching for the optimal way to monitor these patients.
In a study on early detection of ovarian cancer using the Risk of Ovarian Cancer Algorithm (ROCA), CA125 was frequently tested in women with high risk who chose to postpone surgery. The study included 3692 women with either a strong familial history of breast and/or ovarian cancer, or BRCA1/2
mutations. Patients were screened every 3 months for significant increases in their CA125 baseline.
Co-lead author Steven J. Skates, PhD, co-developer of the ROCA, says that this approach improves on current screening techniques; however, he adds that it is important to remember the success of preventative surgery.
“Surgery essentially reduces the risk down to normal levels, and screening will not make it that far. But, for those high-risk women who want to delay surgery despite standard medical advice to the contrary and want to have surveillance in the meantime, I think we've made a step toward providing a more effective way to do that and there is a clear path ahead of us to improve even more.”
In an interview with OncLive
, Skates, of the Massachusetts General Hospital Cancer Center and the Biostatistics Unit, says that the best option for women who choose to postpone surgery is frequent CA125 testing with the ROCA.
OncLive: Could you provide some background information on this study?
We started this back in 2000, and at that time, we thought that early detection of ovarian cancer by repeating screening might be a better way to find the cancer in early stages than what was being done at the time. We assembled 2 cohorts, 1 was through the National Cancer Institute’s (NCI) Cancer Genetics Network, and that was the main component of that cohort—although there were additional NCI groups that contributed to that—but in total, about 2500 women. Around the same time, the Gynecologic Oncology Group (GOG) was planning a study in women who were choosing between prophylactic oophorectomy and surveillance. The surveillance arm used this longitudinal CA125 approach that I developed in the late 1990s. GOG began this study in 2003 and enrolled about 1500 women—so in total we had about 4000 women.
We were using this longitudinal CA125 ROCA to determine whether a significant rise in CA125 above each woman's personal baseline may indicate they have ovarian cancer. ROCA was based on prior screening studies where the CA125 blood samples were taken on a regular basis and interpreted with a cut point. In retrospective analysis of those studies, it was pretty clear that those that had ovarian cancer had a rising CA125 before diagnosis. From this retrospective analysis we developed the longitudinal algorithm and implemented it in prospective screening studies. In the prospective studies, when the algorithm identified a rise resulting in an intermediate risk, we flagged them for referral to ultrasound. If it was a sufficiently large rise to result in an elevated risk, we referred them to ultrasound and a review by a gynecologic oncologist.
Then, following completion of two retrospective studies on women who had undergone RRSO which found that it reduced the risk of ovarian cancer by 95%, RRSO became the standard of care for women at high risk. We continued to follow and screen the women enrolled in the 2 cohorts who did not want to undergo immediate surgery. In reporting results for women who did not want to undergo immediate surgery, despite the fact that RRSO is the standard medical advice, instead of looking at CA125 at 1 point in time and evaluating that, we established a baseline for each woman, and a variation about that baseline. From there we looked for significant rises above that baseline when compared to the variation. Once the 2 cohort studies were completed, we reported the results in Clinical Cancer Research.
What do you want community oncologists to take away from this report?
The first thing I want to emphasize, is that this isn't, in any way, shape, or form, a replacement for RRSO. That is still the standard of care and still gives the patient far better protection. However, if, for whatever reason, the patient decides not to undergo immediate preventative surgery, then this is a better option for finding ovarian cancer early, or, reducing the risk of diagnosis for advanced ovarian cancer.