Abstract
INTRODUCTION: Older adults living with Alzheimer's disease and related dementias (ADRD) who are then diagnosed with cancer are an understudied population. While the role of cognitive impairment during and after cancer treatment have been well-studied, less is understood about patients who are living with ADRD and then develop cancer. The purpose of this study is to contribute evidence about our understanding of this vulnerable population. MATERIALS AND METHODS: This was a retrospective cohort study of a linked, representative family of databases of cancer registries and Medicare administrative claims that make up the SEER-Medicare database. Older adults ages 68 and older with a first primary cancer type: breast, cervical, colorectal, lung, oral, or prostate were eligible for inclusion (N = 337,932). Prevalence estimates of ADRD across cancer types and a 5% non-cancer comparison sample were compared by patient factors. RESULTS: The overall prevalence of patients who had an ADRD diagnosis anytime in the three years prior to their cancer diagnosis was 5.6%. Patients with ADRD were more likely to be female, older (over age 75), a racial/ethnic minority, single, with multiple chronic conditions, and a tumor diagnosed early (stage I) or were unstaged. Black patients with colorectal and oral cancer had the highest and second highest prevalence of ADRD compared to White patients (13.46% vs 7.95% and 12.64% vs 7.82% respectively, p < .0001). We observed the highest prevalence of ADRD among Black patients for breast (11.85%), cervical (11.98%), lung (8.41%), prostate (4.83), and the 5% sample (9.50%, p > .0001). DISCUSSION: The higher prevalence of ADRD among Black and Latine older adults with cancer not only aligns with the trend observed in our non-cancer comparison sample, but also, these findings demonstrate the compounded risk experienced by minoritized older adults over the life course. The greater than expected prevalence of patients with ADRD who go on to develop cancer demonstrates better assessment of cognition is urgently needed. Accurate identification of these vulnerable populations is critical to improve assessment, care coordination, and address inequities in screening and treatment planning.