Tubal contraception and ovarian cancer risk: a global view

Intrauterine device use and risk of ovarian cancer: Results from the New England Case-Control study and Nurses' Health Studies

Results of studies assessing intrauterine device (IUD) use and ovarian cancer risk are inconsistent. We examined the association between IUD use, including duration, type and timing of use, and ovarian cancer risk using three population-based studies. Data from the New England Case-Control Study (NEC) and two prospective cohort studies, the Nurses' Health Studies (NHS/NHSII), were included in the analysis. Information on IUD use was collected by in-person interview in NEC and by biennial questionnaire in NHS/NHSII. We used unconditional logistic regression to calculate odds ratios (OR) and 95% confidence intervals (CI) in NEC and Cox regression to calculate hazard ratios (HR) and 95% CI in NHS/NHSII. We used meta-analysis to combine the NEC and the pooled NHS/NHSII results. Overall, IUD use was not associated with epithelial ovarian cancer risk (OR = 0.96, 95% CI: 0.81-1.14 in NEC; HR = 0.89, 95% CI: 0.69-1.15 in NHS/NHSII; combined RR = 0.94, 95% CI: 0.81-1.08). Among IUD users, older age at first use was associated with increased ovarian cancer risk (P-trend = .03). We did not observe significant associations by IUD type or duration of use. In conclusion, IUD use was not associated with ovarian cancer risk in our study.

What are the mechanisms of action of the different contraceptive methods to reduce the risk of ovarian cancer?

OBJECTIVE

Ovarian cancer (OvCa) is the deadliest gynaecologic malignancy. Knowing that OvCa, as a disease, has different origins has allowed us to relate them to the mechanisms of action of different contraceptive methods with the aim of evaluating the possibility of their use in reducing risk.

STUDY DESIGN

This commentary review article will instead focus on the recent findings on the role of contraceptive methods in preventing of OvCa.

RESULTS

Combined hormonal contraceptive (CHC) use is an effective method of chemoprevention for OvCa in the general population and in women with genetic disorders. Salpingectomy, better than tubal ligation, should be offered for ovarian/tubal/peritoneal cancer prevention. Progestogen-only methods can decrease the risk of OvCa via reduced menstrual bleeding and by changes in the hormonal environment that surrounds the ovary. IUDs of any type, through different mechanisms, decrease the risk of OvCa. Barrier methods prevent the passage of germs into the tubes and ovaries and the inflammatory state they produce.

CONCLUSIONS

Most contraceptive methods have a mechanism of action that may favour a reduction in the risk of OvCa. The theories of incessant ovulation, retrograde menstruation, and that the fallopian tubes are the site of origin of a proportion of high-grade serous OvCa, have led to the recommendation that anovulatory methods, those that decrease menstrual bleeding, and those that blocked tubes, or even better, 'opportunistic salpingectomy' are a current approach to prevent OvCa in the population general and, above all, in the population at risk.

Contraception options for patients with known hereditary risk for ovarian cancer

For patients with a known hereditary risk of ovarian cancer, primary prevention typically is accomplished through prophylactic bilateral salpingo-oophorectomy. However, some patients may wish to preserve fertility or delay menopause and its associated comorbidities. This article discusses appropriate methods of contraception for these patients.

Current Gaps in Ovarian Cancer Epidemiology: The Need for New Population-Based Research

With recent ovarian cancer screening studies showing no clinically significant mortality benefit, preventing this disease, identifying high-risk populations, and extending survival remain priorities. However, several challenges are impeding progress in ovarian cancer research. With most studies capturing exposure information from 10 or more years ago, evaluation of how changing patterns of exposures, such as new oral contraceptive formulations and increased intrauterine device use, might influence ovarian cancer risk and survival is difficult. Risk factors for ovarian cancer should be evaluated in the context of tumor histotypes, which have unique molecular features and cells of origin; this is a task that requires large collaborative studies to achieve meaningful sample sizes. Importantly, identification of novel modifiable risk factors, in addition to those currently known to reduce risk (eg, childbearing, tubal ligation, oral contraceptive use), is needed; this is not feasibly implemented at a population level. In this Commentary, we describe important gaps in knowledge and propose new approaches to advance epidemiologic research to improve ovarian cancer prevention and survival, including updated classification of tumors, collection of data on changing and novel exposures, longer follow-up on existing studies, evaluation of diverse populations, development of better risk prediction models, and collaborating prospectively with consortia to develop protocols for new studies that will allow seamless integration for future pooled analyses.