Oral contraceptive birth control reduces risk for aggressive ovarian cancer
ATLANTA — Oral contraceptive use appeared associated with a reduced risk for highly fatal aggressive ovarian cancer, with a greater risk reduction observed with longer birth control use, according to study results presented at American Association for Cancer Research Annual Meeting.
Although it has been known that oral contraceptive use reduces the risk for ovarian cancer, this is the first study to show the risk reduction is driven by a lower incidence of aggressive and highly fatal subtypes of ovarian cancer.
“The longer the history of oral contraceptive use, the greater the protection we observed in terms of reduced chance of dying [of] aggressive ovarian cancer,” Jennifer M. Mongiovi, graduate student at Roswell Park Comprehensive Cancer Center and cancer epidemiology fellow in the department of epidemiology and environmental health at University at Buffalo, said in a press release. “For every 5 years of use, we observed 32% lower odds of highly fatal disease, compared to 13% for all ovarian cancer as previously reported by other researchers. This association also varies by histological subtype, and was found most protective for highly fatal endometrioid ovarian cancers.”
Mongiovi and colleagues used data from 20 case-control studies in the Ovarian Cancer Association Consortium to evaluate the association between prediagnostic oral contraceptive use and highly fatal ovarian cancer, defined as mortality within 12 or 18 months of diagnosis.
The analysis included 579 women who died within 12 months of their diagnosis, matched 1:4 by 5-year age categories, race and study site to 2,279 controls, as well as 1,294 patients who died within 18 months matched to 5,095 controls.
Analyses adjusted for age, site and parity showed any oral contraceptive use was associated with a 46% reduction in the odds of death within 12 months (OR = 0.54; 95% CI, 0.43-0.68).
Researchers then conducted separate models for duration of oral contraceptive use per 5-year increase. Results showed a 66% reduction in odds of death within 12 months for those who used oral contraceptives for more than 10 years (OR = 0.34; 95% CI, 0.23-0.49), whereas there was no significant risk reduction for those who used oral contraceptives for 1 year or less (OR = 0.83; 95% CI, 0.6-1.14).
These trends appeared consistent among women who died within 18 months; however, oral contraceptive use appeared more protective among highly fatal cases, or those who died within 12 months.
Use of oral contraception appeared most protective for endometrioid subtypes among those who died within 12 months (OR = 0.43, 95% CI, 0.2-0.93) and 18 months (OR = 0.39, 95% CI, 0.23-0.65).
“Our results provide strong evidence that this is an area worthy of further study so that we can better understand the mechanisms behind this association and identify specific groups of people who may benefit most from this chemopreventive strategy,” senior author Kirsten Moysich, PhD, MS, distinguished professor of oncology in the departments of cancer prevention and control and immunology at Roswell Park, said in the press release. – by Alexandra Todak
Mongiovi JM, et al. Abstract 641/25. Presented at: AACR Annual Meeting; March 29-April 3, 2019; Atlanta.
Disclosures: The authors report no relevant financial disclosures.