Association between financial toxicity and frailty among older patients with cancer: a cross-sectional study using COST and G8

PURPOSE: Financial toxicity (FT) is increasingly recognized as a critical challenge in cancer care. Older patients can be particularly vulnerable due to frailty-related impairments and accumulated treatment burden. This study aimed to evaluate FT and its association with geriatric vulnerability among older patients with cancer. METHODS: We conducted a single-center cross-sectional study of patients aged ≥ 65 years with cancer treated at a regional hospital in Japan. FT was assessed using the Comprehensive Score for Financial Toxicity (COST) instrument. Frailty-related vulnerability was evaluated using questionnaire-based assessments, including the G8 screening tool. Associations between the COST score and clinical variables were examined using univariate and multivariable linear regression analyses. Supplementary analyses were performed using the conventional G8 cutoff value (≤ 14). RESULTS: Ninety-one patients aged ≥ 65 years were included. The median COST score was 25 (range, 8-44). Lower G8 scores were significantly associated with greater FT (Pearson's r = 0.345, p = 0.001). In the multivariable analysis, lower G8 scores (p = 0.048), poorer health-related quality of life (p = 0.036), and the receipt of multimodal therapy (p = 0.013) were independently associated with greater FT. Similar findings were observed when the G8 score was analyzed using the conventional cutoff value. CONCLUSION: Among older patients with cancer, FT was independently associated with geriatric vulnerability assessed by the G8 screening tool, in addition to health-related quality of life and treatment burden. The assessment of geriatric vulnerability may complement conventional socioeconomic indicators in identifying patients at an increased risk of FT.