Comprehensive geriatric assessment in older women with breast cancer: frailty, nutritional vulnerability and impact on treatment decision-making.

This study aimed to provide a comprehensive oncogeriatric characterization of older women with breast cancer treated in the Chilean public health system and to explore the association between geriatric domains, particularly frailty and nutritional status, treatment decision-making, and early treatment-related toxicity. We conducted a retrospective observational cohort study that included 177 women aged ≥60 years (median age 79 years; range 60-95 years) who underwent a comprehensive geriatric assessment at the Instituto Nacional del Cáncer. Frailty was highly prevalent, with 56% of patients classified as vulnerable or mildly frail (a score on the Clinical Frailty Scale of 4 or 5) and 20.4% as moderately or severely frail (score on the Clinical Frailty Scale of 6-9). Nutritional vulnerability was also common, with a mean Mini Nutritional Assessment-Short Form score of 11.1, low muscle strength (mean handgrip 14.7 kg), and reduced calf circumference in 75.7% of patients, despite a mean body mass index in the overweight range (28.1 kg/m2). Most tumours were early stage and hormone receptor-positive; however, frailty, oncogeriatric cluster classification, and nutritional status were significantly associated with therapeutic intent and early treatment-related toxicity (all p < 0.05). Performance status underestimated multidimensional vulnerability compared with geriatric assessment. Treatment plans were modified following geriatric assessment in 40.1% of the cases. Overall, older women with breast cancer treated in the Chilean public health system exhibit a high burden of multidimensional vulnerability that is significantly associated with oncological decision-making and treatment-related outcomes. Comprehensive geriatric assessment provides clinically relevant information beyond traditional oncological metrics and should be systematically integrated into breast cancer care.