Western Regional Blog – BC, YK, AB, NWT and Nunavut
Oral Contraceptive Pills as Primary Prevention for Ovarian Cancer: A Systematic Review and Meta-analysis
Peter Kovacs, MD, PhD
Havrilesky LJ, Moorman PG, Lowery WJ, et al Obstet Gynecol. 2013;122:139-147
Ovarian cancer is the fifth leading cause of cancer death among women. It typically is diagnosed at an advanced stage, when treatments are no longer effective, and therefore the associated mortality is high.
There are no screening tools that could be effectively applied to an otherwise average-risk population and could help early diagnosis. Therefore, any tool that lowers the incidence of ovarian cancer should be offered to women. This review assessed the available evidence regarding oral contraceptive (OC) use and subsequent risk for ovarian cancer.
Fifty-five case/control and cohort studies were included in the analysis. Ever-use of OC, duration of use, age at first use, time since last use, and the effect of different formulations were assessed.
The combined analysis these studies found an ovarian cancer risk reduction with ever-use of OC: odds ratio, 0.73 (95% confidence interval [CI], 0.66-0.81). On the basis of the incidence of ovarian cancer, 185 women would be needed to be treated to prevent 1 case of cancer.
The risk reduction with OC increased with the duration of use. Women with more than 10 years of OC use can expect a greater than 50% reduction in their risk of being diagnosed with ovarian cancer. A protective effect was seen as early as after 1 year of use.
The protective effect decreases with time since last use and is no longer significant when more than 20 years have passed since the last use of OC. The authors did not find a difference among pills with various estrogen or progestin doses. A reduction in ovarian cancer associated mortality was also found with OC use.
In Vitro Fertilization and Risk of Breast and Gynecologic Cancers: A Retrospective Cohort Study Within the Israeli Maccabi Healthcare Services
Brinton LA, Trabert B, Shalev V, Lunenfeld E, Sella T, Chodick G Fertil Steril. 2013;99:1189-1196
Participants of this retrospective cohort study, over 87,000 women with fertility problems, were identified from the database of an HMO. Cancer cases were identified from a cancer registry, and the 2 databases were linked.
Among the entire infertile cohort, 77.4% has received fertility treatment. The mean age at study entry was 31.1 years, and the mean follow-up was 8.1 years. During the follow-up period, 522 breast, 41 endometrial, 45 ovarian, and 32 invasive cervical cancers were identified.
Higher body mass index was associated with endometrial cancer, increased parity was associated with lower ovarian and breast cancer risk, and smoking was positively linked with cervical cancer. These and other known risk factors were controlled for during the analysis.
Women who had received fertility treatment were not found to be at an increased risk for breast cancer (hazard ratio [HR], 0.87; 95% CI, 0.71-1.06), ovarian cancer (HR, 0.9; 95% CI, 0.45-1.79), or endometrial cancer (HR, 1.25; 95% CI, 0.55-2.84) compared with unexposed infertile women. The risk for cervical cancer was lower among women exposed to fertility therapy. There was a trend toward higher risk for ovarian cancer among women undergoing 1-3 in vitro fertilization (IVF) cycles (HR, 1.94; 95% CI, 0.73-5.12).