Description:
Abstract Links between cancer history and incident stroke have been established, such that 15% of cancer patients experience a stroke at some point during their clinical course. However, we do not know whether stroke history is associated with cancer risk, especially for those cancers with overlapping risk factors with stroke. To address this, we used data from the observational and clinical trial of the Women's Health Initiative (n = 145,075), to test whether stroke history was associated with cancer risk and tumor type, and whether variation in cancer risk and tumor type exist by race/ethnicity. Time to incident cancer (in months) was estimated with bivariate and multivariate adjusted cox proportional hazards models, accounting for competing risks, comparing women with incident or prevalent stroke to women without stroke at baseline or at any point during follow-up, and models were stratified by race/ethnicity. Women with a stroke history, compared to those without, had significant differences in the following baseline characteristics: age, body mass index, smoking status, hormone replacement therapy usage, hypertension, hypercholesterolemia and diabetes, and differences were consistent among race/ethnic groups. In unadjusted and adjusted competing risk models of the overall sample, lower cancer risk was observed for women who had a prior stroke, compared to those with no stroke history (adjusted HR: 0.81; 95% CI: 0.75, 0.88). In race-stratified models, Non-Hispanic White (NHW) women experienced significantly lower risk of cancer following stroke, compared to those with no stroke history (adjusted HR: 0.81; 95% Confidence Interval: 0.74-0.89), and the magnitude of the association was similar, although not significant, for African American (AA) and ‘Other’ racial/ethnic groups. The associations with stroke were stronger for African American women with invasive breast (p = 0.02), lung (p = 0.04), and ‘other’ (p = 0.001) cancers, compared to NHW women. The results of the current study suggest that overall, women have lower cancer risk post-stroke, but that AA women, compared to their NHW counterparts, have higher risk of certain types of cancers after stroke. Future studies should investigate the mechanisms underlying the lower cancer risk among all stroke survivors, as well as examine why AA women develop certain tumors more often than NHW women. Citation Format: Shawnita Sealy-Jefferson, Michele L. Cote, Jennifer Beebe-Dimmer, Rowan Chlebowski, Kathryn Rexrode, Michael Simon. An evaluation of the post-stroke cancer risk among post-menopausal women: The Women's Health Initiative. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1766.