Prospective Observational Study Evaluating the Prognostic Value of the G8 Screening Tool for Extensive-Stage Small Cell Lung Cancer Patients Who Received Programmed Death-Ligand 1 Inhibitor plus Platinum–Etoposide Chemotherapy

Background Programmed death-ligand 1 (PD-L1) inhibitor plus platinum–etoposide chemotherapy is used as a first-line treatment for extensive-stage small cell lung cancer (ES-SCLC), regardless of age. Objective We examined the role of the Geriatric 8 (G8) screening tool for evaluating treatment outcomes in patients with ES-SCLC treated with PD-L1 inhibitor plus platinum–etoposide chemotherapy as first-line therapy. Patients and Methods Between September 2019 and October 2021, we prospectively evaluated patients with ES-SCLC treated with immunochemotherapy at ten institutions in Japan. The G8 score was assessed before treatment initiation. Results We evaluated 44 patients with ES-SCLC. Patients with G8 score > 11 had longer overall survival (OS) than those with G8 score ≤ 11 (not reached versus 8.3 months; log-rank test, p = 0.005). In univariate and multivariate analyses, G8 score > 11 [hazard ratio (HR) 0.34; 95% confidence interval (CI) 0.15–0.75; p = 0.008 and HR 0.34; 95% CI 0.14–0.82; p = 0.02, respectively) and performance status (PS) of 2 (HR 5.42; 95% CI 2.08–14.2; p < 0.001 and HR 6.94; 95% CI 2.25–21.4; p < 0.001, respectively) were independent prognostic factors for OS. Among patients with good PS (0 or 1), the OS in patients with G8 score > 11 was significantly longer than that in patients with G8 score ≤ 11 (not reached versus 12.3 months; log-rank test, p = 0.02). Conclusions G8 score evaluation before treatment initiation was useful as a prognostic factor for ES-SCLC patients who received PD-L1 inhibitors and platinum–etoposide chemotherapy, even with good PS.