Recreational Physical Activity and Ovarian Cancer Risk and Survival

PURPOSE: Physical activity may influence ovarian cancer risk and outcomes through effects on ovulation, inflammatory markers, and other processes. We examined associations between self-reported physical activity and ovarian cancer risk and survival in a population-based, case-control study in North Carolina. METHODS: The analyses involved 638 epithelial ovarian cancer cases and 683 controls recruited between 1999-2008. Logistic regression analyses were used to assess ovarian cancer risk in relation to reported average physical activity at various time periods. Kaplan-Meier analyses and proportional hazards modeling were used to assess associations between physical activity and survival among ovarian cancer cases. RESULTS: Modestly reduced risks for ovarian cancer were observed in some categories of physical activity, but there were no consistent patterns of greater reductions in risk with higher activity levels. Physical activity before diagnosis was not significantly related to ovarian cancer survival overall, but survival was better for women who reported greater than 2 hours of activity/week as compared to those reporting less than 1 hour/week among women who were non-obese (multivariable Hazard ratio = 0.69, 95% confidence interval: 0.47-1.00). CONCLUSIONS: Our data provide weak evidence in support of beneficial effects of physical activity on ovarian cancer risk and survival, but results should be interpreted cautiously because of the lack of a clear dose response relation with higher levels of exercise and the likely misclassification of self-reported activity. Ann Epidemol 2011;21:178-187. (C) 2011 Elsevier Inc. All rights reserved.