Validation of a 10-item frailty index based on a comprehensive geriatric assessment (FI-CGA-10) for predicting survival in older adults with cancer.

1656 Background: The FI-CGA-10 is a content- and construct-validated measure for quantifying frailty from a CGA [Oncologist, 26, e1751 (2021)]. For criterion validation, we evaluated the predictive validity of the FI-CGA-10 for survival in older adults with cancer. Methods: This prospective cohort study included 1,630 consecutive older adults with cancer who underwent CGA prior to their cancer treatment decision at a geriatric oncology service in Japan from September 2018 through September 2024. Fitness and frailty were evaluated using the FI-CGA-10, which comprises ten domains: cognition, mood, communication, mobility, balance, nutrition, basic and instrumental activities of daily living (ADLs/IADLs), social support, and comorbidity. Deficits in each domain were scored 0 (no problem), 0.5 (minor problem), or 1.0 (major problem). FI-CGA-10 scores were calculated as the sum of domain scores divided by 10 and categorized as fit (<0.20), pre-frail (0.20–0.35), and frail (>0.35). The primary outcome was overall survival (OS) at 1 year from the date of CGA. Two Cox proportional hazards models were fitted to predict 1-year overall survival (OS): a base model (age, sex, cancer type, and stage) and the base model plus the FI-CGA-10 as a categorical variable. Model performance was compared using the likelihood ratio test and Harrell’s c-index. We also examined associations between each FI-CGA-10 domain and 1-year OS, adjusting for the same covariates. Results: Median age was 80 years (range, 51–99); 61% were male, 46% had gastrointestinal cancer, and 41% had distant-stage disease. Overall, 22% were fit, 38% pre-frail, and 40% frail; 29% died within one year. By the likelihood ratio test, adding the FI-CGA-10 significantly improved model fit compared with the base model (LR χ² = 140.7; P < .001). Adding the FI-CGA-10 also significantly improved discrimination (c-index 0.70 vs 0.76; P < .001). Kaplan–Meier curves for the three groups showed clear separation, demonstrating the FI-CGA-10’s discriminatory ability (log-rank P < .001). After adjustment for covariates, pre-frail (HR 2.26; 95% CI 1.61–3.19) and frail (HR 5.06; 95% CI 3.64–7.04) patients had higher hazards of death versus fit patients. Estimated 1-year OS probabilities were 90% (fit), 78% (pre-frail), and 58% (frail). In multivariable analyses adjusted for age, sex, cancer type, and stage, major problems in all domains—and minor problems in cognition, mobility, balance, nutrition, IADL, and comorbidity—were significantly associated with worse survival compared with no problems. Conclusions: These findings support the predictive validity of the FI-CGA-10 for 1-year OS in older adults with cancer. Together with prior work demonstrating its content and construct validity, the FI-CGA-10 satisfies core components of measurement validation that can help clinicians care for older cancer patients.