Validation of a chemotherapy toxicity prediction model in older adults with cancer in Taiwan.

223 Background: The Cancer and Aging Research Group (CARG) model is established for predicting chemotherapy-related toxicities in older patients; however, its applicability has not been validated in Taiwanese or non-solid tumor populations. Due to biopsychosocial distinctions in the Taiwanese demographic and inherent disparities between lymphoma and solid tumors, a modified CARG (mCARG) was assessed for its toxicity prediction capabilities. Methods: In this study, 337 consecutive patients aged ≥65 years with solid tumors (N=258) or lymphoma (N=79), slated for first-line chemotherapy, were recruited from a single medical center in Taiwan between 2018 and 2021, with follow-up until December 31, 2021. Patients were categorized into low-, medium-, and high-risk groups based on mCARG, excluding the cancer-type parameter from the original CARG variables. Validation of mCARG involved receiver operating characteristic (ROC) curves, and individual mCARG variables were analyzed using univariate analysis for their impact on chemotherapy toxicities and overall survival. Results: This study included 337 patients (mean age, 70 years; 160 female 47%; 177 male 53%) classified as low-(N=112, 33.2%), medium-(N=106, 31.5%), and high-(N=119, 35.3%) risk. Toxicities of grades ≥3 were 41.1%, 50.0%, and 71.4% ( P<0.001), respectively. ROC was 0.665 (95% CI: 0.608–0.722), indicating satisfactory discrimination. However, the lymphoma subgroup exhibited no significant differences in toxicity risk levels (70.0%, 74.1%, and 81.0%; P=0.39). Among mCARG variables, age ≥72 years ( P=0.008), polychemotherapy ( P=0.009), decreased hemoglobin ( P<0.001), falls ( P=0.008), and inability to walk one block ( P=0.01) were associated with toxicities. One-year overall survival rates were 80.6%, 69.4%, and 57.2%, respectively, in ascending-risk groups, with high-risk groups showing decreased survival ( P=0.001). Conclusions: This prognostic study validated the mCARG model in a heterogeneous cancer cohort in Taiwan but failed to do so in the lymphoma subgroup. Although unable to predict all toxicities, mCARG could offer insights into patient survival among older individuals with cancer.