Abstract
Ovarian cancer is the deadliest gynecologic cancer. Chronic stress accelerates tumor growth in animal models of ovarian cancer. We therefore postulated that posttraumatic stress disorder (PTSD) may be associated with increased risk of ovarian cancer. We used data from the Nurses' Health Study II, a longitudinal cohort study with 26 years of follow-up, conducted from 1989 to 2015 with 54,710 subjects. Lifetime PTSD symptoms were measured in 2008. Self-reported ovarian cancer was validated with medical records. Risk of ovarian cancer was estimated with Cox proportional hazards models and further adjusted for known ovarian cancer risk factors (e.g., hormonal factors) and health risk factors (e.g., smoking). Fully prospective secondary analyses examined incident ovarian cancer occurring after PTSD assessment in 2008. In addition, we examined associations by menopausal status. During follow-up, 110 ovarian cancers were identified. Women with high PTSD symptoms had 2-fold greater risk of ovarian cancer versus women with no trauma exposure [age-adjusted HR = 2.10; 95% confidence interval (CI), 1.12-3.95]. Adjustment for health and ovarian cancer risk factors moderately attenuated this association (HR = 1.86; 95% CI, 0.98-3.51). Associations were similar or moderately stronger in fully prospective analyses (age-adjusted HR = 2.38; 95% CI, 0.98-5.76, N cases = 50) and in premenopausal women (HR = 3.42; 95% CI, 1.08-10.85). In conclusion, we show that PTSD symptoms are associated with increased risk of ovarian cancer. Better understanding of the underlying molecular mechanisms could lead to interventions that reduce ovarian cancer risk in women with PTSD and other stress-related mental disorders. SIGNIFICANCE: PTSD is associated with ovarian cancer risk, particularly in premenopausal women. Understanding the underlying molecular mechanisms will aid in formulating ways to reduce ovarian cancer risk associated with chronic stress.