Purpose <p>The incidence and prevalence of both cancer and dementia is rapidly increasing. Older adults with cognitive impairment (CI) may be more susceptible to adverse outcomes when diagnosed with cancer. The primary objective of this study was to examine the impact of CI on overall survival for post-menopausal women before and after a cancer diagnosis.</p> Methods <p>Data from the Women’s Health Initiative (WHI) Life and Longevity After Cancer (LILAC) study were used to examine overall survival of a unique cohort of LILAC participants screened for cognitive impairment. Cox proportional hazards regression was used for overall survival.</p> Results <p>592 participants were included in the analysis. Median age was 76 (range 73–79). 15.5% of participants had CI prior to their cancer diagnosis and 17.7% of patients had CI ever. All cancer types were included with the majority having breast (44%), lung (18%), and colorectal (18%). In a regression analysis, pre-existing CI (HR 1.48, 95%CI 1.11–1.97) and CI ever (pre- or post-diagnosis) (HR 1.66, 95%CI 1.20–2.29) were associated with worse overall survival. However, these associations were not significant following adjustments for prognostic factors of survival, CI pre (HR 1.23, 95%CI 0.91–1.67) and CI ever (HR 1.26, 95%CI 0.88–1.80).</p> Conclusion <p>The association between CI and overall survival was not significant when adjusted for covariates. The sample size was small and included mostly white females with breast cancer. A larger sample with additional sub analysis will be important to examine overall survival in this population.</p>