Background: Diffuse large B-cell lymphoma (DLBCL) is a potentially curable cancer, predominantly affecting older patients. Functional limitations and comorbidities make its management challenging among those with advanced age. Approximately 23% of Medicare beneficiaries do not receive curative chemoimmunotherapy (Hamlin et al, Oncologist, 2014), and the treatment rates decrease with increasing age (Williams et al, Cancer, 2015). Treatment may be particularly difficult for older nursing home (NH) residents who are physiologically frail and have significant functional limitations. The goal of this study is to describe patterns of cancer-directed therapies and outcomes among NH residents with DLBCL in the United States and dissect the association between functional impairment and receipt of treatment.Methods: We used the SEER-Medicare registry to identify Medicare beneficiaries diagnosed with DLBCL in 2011-2015, who had Minimum Data Set (MDS) assessments within 120 days prior to diagnosis or treatment. The MDS is routinely performed in NHs and includes multiple geriatric domains, including physical and cognitive function. We used the Morris activities of daily living (ADL) scale to quantify functional limitations in 7 activities (bed mobility, dressing, eating, locomotion on unit, personal hygiene, toileting, and transfers). We characterized limitations based on dependency in ADLs: no disability (0 ADLs), moderate disability (1-4 ADLs), or severe disability (5-7 ADLs). We used the Cognitive Function Scale (CFS) to characterize cognition as intact, mild, or moderate to severe impairment. We used multivariable logistic regression to compare the receipt of chemoimmunotherapy (including receipt of curative multiagent, anthracycline-containing regimen), 30-day mortality, and 30-day hospitalization, respectively, between the NH and non-NH population, reporting the odds ratio (OR) and 95% confidence interval (CI). We used multivariable Cox regression to compare overall survival (OS) between these two populations, reporting hazard ratio (HR) with 95% CI. Within the NH population, we examine the association of receipt of chemotherapy with functional and cognitive impairment, respectively. All models were adjusted for age, sex, race, stage, comorbidities, Medicaid dual coverage, and type of NH stay (long vs. short stay).Results: Among 11,128 patients with DLBCL, 718 received care in NHs (median age 82 years, 59% women, 90% White, 50% stage III/IV disease). Compared with non-NH patients, NH residents were less likely to receive any chemoimmunotherapy (41% vs. 69%, OR: 0.34, 95% CI: 0.29-0.41) or, when treated, curative regimens (47% vs. 71%, OR: 0.51, 95% CI: 0.37-0.72) (Fig. 1A-1B). NH residents had high rates of 30-day mortality after therapy (18% vs. 7%, OR: 1.99, 95% CI: 1.43-2.77) and 30-day hospitalization (58% vs. 43%, OR: 1.51, 95% CI: 1.18-1.93), and had short median OS of 3.7 months (versus 31.7 months for non-NH residents; HR: 1.36, 95% CI: 1.11-1.65) (Fig. 1C).Rates of disability and cognitive impairment were high, 20% had moderate disability, 60% had severe disability and 17-26% had mild or moderate to severe cognitive impairment. Compared with patients with no ADL disability, those with severe disability were less likely to receive any chemoimmunotherapy (38% vs. 50%, OR: 0.58, 95% CI: 0.38-0.89) (Fig. 2A-2B). Compared with those with intact cognitive function, patients with mild (39% vs. 47%, OR: 0.66, 95% CI: 0.45-0.97) and moderate to severe (24% vs. 47%, OR: 0.31, 95% CI: 0.19-0.51) impairment, respectively, were less likely to receive chemoimmunotherapy (Fig. 2C).Conclusions: In this population-based study, over half of NH residents with DLBCL did not receive chemoimmunotherapy, and 47% of chemotherapy recipients received curative regimens. Despite treatment, NH residents had higher rates of early mortality and hospitalization, and short median survival (only 3.7 months). These findings indicate a need for alternative treatment strategies for patients in NHs, particularly those with high levels of disability. Routinely collected NH assessment data revealed strong associations between receipt of chemotherapy, functional limitations, and cognitive impairment among NH residents with DLBCL. These findings suggest that structured assessment of function and cognition may improve patient selection for curative therapy. [Display omitted] DisclosuresOlszewski: TG Therapeutics: Research Funding; PrecisionBio: Research Funding; Celldex Therapeutics: Research Funding; Genentech, Inc.: Research Funding; Acrotech Pharma: Research Funding; Genmab: Research Funding. Panagiotou: International Consulting Associates, Inc: Other: Personal fees.