A Multi-Center Comparative Analysis of the G8-Score and Charlson Comorbidity Index as General Health Assessment Tools in Older Patients With Prostate Cancer.

[INTRODUCTION] Frail and older patients who develop prostate cancer (PCa), are at risk of overtreatment. Multiple general health assessment (GHA) tools have been validated in oncology. we aim to validate and compare the performance of the G8 screening tool, age and Charlson Comorbidity Index (CCI) as a predictor of overall survival (OS) in men older than 70 years with a newly diagnosed prostate cancer. Is it possible to identify a CCI cut-off indicative for frailty?

[PATIENTS AND METHODS] Between 2009 and 2015, a national multicenter initiative on geriatric screening and GHA's took place in Belgium. Baseline characteristics were collected on the date of inclusion on which a specialist nurse completed multiple GHA questionnaires for each patient. We performed a sub analysis on the prostate cancer (n = 182) cohort, ≥ 70 years old. GHA's were compared through multivariate-, Kaplan-Meier- and sensitivity analysis. If indicated, Case-control matching was applied to reduce variate heterogeneity. Ten-year OS is the primary endpoint.

[RESULTS] Men with a G8-score of ≤14 points had a significantly worse OS both in the unmatched: 86.8 months (95% CI: 70.5-103.1) vs. 137.9 months (95% CI: 129.4-146.4) (P < .001) and matched population: 99.3 months (95% CI 81.9-116.73) vs. 136.0 months (95% CI: 121.8-150.2) (P < .05). Defining frailty as the presence of comorbidities (CCI ≥ 1 point) shows inferior (HR:1.3, 95% CI: 0.8-2.1-AUC: 0.583) accuracy compared to the G8-score (HR 2.9, 95% CI 1.8-4.5-AUC: 0.715). If the frailty threshold of the CCI is raised to ≥ 2 points, accuracy is matched (HR 4.9, 95% CI 2.8-8.4-AUC 0.735).

[CONCLUSION] This multicenter analysis validates the predictive value of the G8-score and CCI on OS in newly diagnosed PCa in the older patient. Both GHA's appear more accurate than age. A CCI ≥ 2 points approximates the sensitivity of G8 defined frailty. External validation of these findings is needed.