1. ¹Cancer Prevention Program, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N, M4-B402, Seattle, WA 98109, USA
2. ²Department of Cancer Control, University of Wisconsin Paul P Carbone Comprehensive Cancer Center, Madison, WI 53726, USA
3. ³Department of Risk Assessment, Detection, and Intervention, H Lee Moffitt Cancer Center and Research Institute, Tampa, FL 33612, USA

Correspondence: Dr KJ Wernli, E-mail: kwernli@fhcrc.org

Received 14 February 2008; Revised 30 March 2008; Accepted 9 April 2008.

Abstract

We examined the association between non-steroidal anti-inflammatory drug (NSAID) use and ovarian cancer by potential effect modifiers, parity and oral contraceptive use, in a population-based case–control study conducted in Wisconsin and Massachusetts. Women reported prior use of NSAIDs and information on risk factors in a telephone interview. A total of 487 invasive ovarian cancer cases and 2653 control women aged 20–74 years were included in the analysis. After adjustment for age, state of residence and other covariates, ever use of NSAIDs was inversely associated with ovarian cancer in never users of oral contraceptives (odds ratio (OR)=0.58, 95% confidence interval (CI) 0.42–0.80) but not for ever users (OR=0.98, 95% CI 0.71–1.35) (P-interaction=0.03). A reduced risk with NSAID use was also noted in nulliparous women (OR=0.47, 95% CI 0.27–0.82) but not among parous women (OR=0.81, 95% CI 0.64–1.04) (P-interaction=0.05). These results suggest that use of NSAIDs were beneficial to women at greatest risk for ovarian cancer.