Purpose <p>Diffuse large B-cell lymphoma (DLBCL) is one of the most common and aggressive forms of non-Hodgkin’s lymphoma. This study aimed to evaluate the performance of the abbreviated Comprehensive Geriatric Assessment (aCGA) in assessing frailty and predicting clinical outcomes in elderly patients with DLBCL.</p> Methods <p>A total of 91 patients aged ≥ 65&#xa0;years with newly diagnosed DLBCL and who received immunochemotherapy at a single medical center in Taiwan between August 2019 and December 2022 were prospectively enrolled. Frailty was assessed in all participating patients within seven days of the first cycle of immunochemotherapy. The primary objective was to compare aCGA’s accuracy in assessing frailty with that of the full CGA. Secondary objectives included assessing correlations between frailty and severe adverse events (sAEs), early mortality, and overall survival (OS).</p> Results <p>In the cohort, 50 (55%) and 38 (42%) patients were categorized as frail based on CGA and aCGA, respectively. A high number of aCGA domains impairment were positively associated with a high number of CGA domains impairment. The receiver operating characteristic for aCGA for detecting frailty was 0.846 (95% confidence interval [CI], 0.756–0.926). A cut-off point of ≥ 2 aCGA domain impairments indicated frailty, with a sensitivity of 70.0% and specificity of 92.7%. Based on aCGA, the early mortality rate was 7.5% and 26.3% (p = 0.019) for fit and frail patients, respectively. The 1-year and 2-year OS rates were 77.7% and 67.4% for fit patients, and 57.1% and 45.4% for frail patients, respectively. The adjusted hazard ratio for OS was 2.42 (95% CI, 1.06–5.49, p = 0.035) for frail patients compared to fit patients.</p> Conclusions <p>This finding suggested that aCGA could be used as an efficient alternative to the full CGA, potentially improving the clinical management and treatment decision-making for elderly patients with DLBCL.</p>