Long-term trajectories of functional disability in older adults with cancer

Abstract Background: Older individuals with cancer history have lower risk of developing Alzheimer’s disease (AD). Cognitive impairment is associated with lower functioning in Instrumental Activities of Daily Living (IADL) and Activities of Daily Living (ADL). However, little is known about long-term IADL and ADL trajectories among individuals with cancer, hindering understanding of the underlying biological mechanisms between cancer and AD. We investigated the long-term functional disability trajectories of adults with cancer, comparing them with similarly aged individuals without a cancer diagnosis. Methods: Our study included 16,006 individuals aged 50 and older without a cancer history at baseline from the Health and Retirement Study. Biennial assessments were conducted from 1998 to 2020, including self-reported cancer status, IADL, and ADL. Linear probability models with repeated measures were used to assess IADL and ADL independence probabilities, adjusting for demographic and socioeconomic covariates. Results: Among 16,006 participants (mean [SD] baseline age, 66.1 [9.9] years; 9,169 [57.3%] female), 3,723 (23.3%) reported a cancer diagnosis during follow-up. Before cancer diagnosis, individuals who later developed cancer had a higher probability of IADL independence and experienced a slower decline in independence compared to their similarly aged counterparts who remained cancer-free. Probability of IADL independence was 0.05 lower immediately after cancer diagnosis compared to the pre-cancer phase, followed by accelerated independence losses relative to the pre-cancer period. After diagnosis, the rate of decline in probability of IADL independence remained slower for individuals with cancer than their cancer-free counterparts, but differences in the rate of decline were smaller than prior to cancer diagnosis. Similar trends were observed for ADL independence. Conclusions: We observed a decline in both IADL and ADL independence around the time of cancer diagnosis, possibly attributed to treatments. Overall, individuals with cancer experienced a more gradual loss in functional independence compared to individuals who remained cancer-free, consistent with the documented inverse association between cancer and AD. Funding information: The current research was supported by the National Cancer Institute of the National Institutes of Health (T32CA009142), T32 Training Grants from the NCI/NIH, and the National Institute on Aging (RF1AG059872). Citation Format: Gina E. Nam, Elizabeth Rose Mayeda, Zuo-Feng Zhang. Long-term trajectories of functional disability in older adults with cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2228.