RISK OF DEMENTIA IN CANCER SURVIVORS: A NATIONWIDE COHORT STUDY

Abstract Background Several observational studies have identified a positive association between cancer survivors and subsequent dementia whereas others have negative or no association. Aims & Objectives This study aimed to determine the association in Taiwanese patients using a large, community-based national claim data. Method Using the Taiwan National Health Insurance Research Database, we recruited 32,250 patients surviving malignancies and 322,500 controls between 1998 and 2011 and followed them up until the end of 2013. A diagnosis of dementia, Alzheimer’ s disease (AD), vascular dementia (VaD), and unspecified dementia were identified during the follow-up period. Cox regression analyses were performed with adjustments for confounders. Sensitivity analysis was conducted to exclude patients with prodromal dementia. Results Cancer survivors were more likely to develop AD (hazard ratio [HR]: 1.68, 95% confidence interval [CI]: 1.38–2.06), unspecified dementia (HR: 1.19, 95% CI: 1.07–1.32), and any dementia (HR: 1.26, 95% CI: 1.16–1.37) compared with controls after adjusting for potential confounders. Specifically, cancers of digestive and genitourinary organs seemed to be associated with such risks, while only malignant neoplasm of the brain was more likely to develop VaD. Sensitivity analyses after exclusion of the first three years or first five years of observation and after exclusion case enrollment before 2009 or 2007 showed consistent findings. Discussion & Conclusion Cancer survivors were associated with higher risk of subsequent dementia. Further studies are necessary to investigate the underlying mechanisms of cancer survivors and dementia.