OBJECTIVE: To estimate the overall reduction in ovarian cancer risk associated with the use of oral contraceptive pills (OCPs) and whether reduction in risk is affected by specifics of OCP use, such as formulation or duration of use.
DATA SOURCES: We searched PubMed, Embase, the Cochrane Database of Systematic Reviews, and ClinicalTrials.gov for studies published from January 1990 to June 2012, with primary analysis of studies published since January 2000.
METHODS OF STUDY SELECTION: We reviewed 6,476 citations. We included English-language controlled studies with human participants reporting a quantitative association between exposure to OCPs (in which the explicit or implicit indication for OCP use was prevention of pregnancy or ovarian cancer) compared with no use of OCPs. Two investigators independently reviewed the title and abstract and full-text of articles for inclusion or exclusion decision; discordant decisions were resolved by team review and consensus.
TABULATION, INTEGRATION, AND RESULTS: Fifty-five studies met inclusion criteria. A random-effects meta-analysis of 24 case-control and cohort studies showed significant reduction in ovarian cancer incidence in ever-users compared with never-users (odds ratio 0.73, 95% confidence interval 0.66–0.81). There was a significant duration–response relationship, with reduction in incidence of more than 50% among women using OCPs for 10 or more years. The lifetime reduction in ovarian cancer attributable to the use of OCPs is approximately 0.54% for a number-needed-to-treat of approximately 185 for a use period of 5 years.
CONCLUSION: Significant duration-dependent reductions in ovarian cancer incidence in the general population are associated with OCP use.
Oral contraceptive pill use is associated with a duration-dependent reduction in ovarian cancer incidence and mortality.
Departments of Obstetrics and Gynecology, Community and Family Medicine, Medicine, and Biostatistics and Bioinformatics, Duke University School of Medicine, the Duke Cancer Institute, Duke University Health System, the Duke Evidence-based Practice Center, Duke Clinical Research Institute, the Center for Health Services Research in Primary Care, Durham Veterans Affairs Medical Center, and the Duke Clinical Research Institute, Durham, North Carolina; and the Department of Obstetrics and Gynecology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina.
Corresponding author: Laura J. Havrilesky, MD, Duke University School of Medicine, Box 3079 DUMC, Durham, NC 27710; e-mail: firstname.lastname@example.org.
Funded under contract no. 290-2007-10066-I from the Agency for Healthcare Research and Quality (AHRQ) and the Centers for Disease Control and Prevention (CDC), United States Department of Health and Human Services. The authors of this report are responsible for its content. Statements in the report should not be construed as endorsement by AHRQ, CDC, or the United States Department of Health and Human Services.
Financial Disclosure The authors did not report any potential conflicts of interest.
The authors thank Liz Wing, MA, for editorial assistance, Kathryn Roth Lallinger, MSLS, and Michael Musty, BA, for project coordination, and Megan von Isenburg, MSLS, for help with the literature search and retrieval.