A monocentric retrospective analysis of 10‑year overall survival after stereotactic body radiotherapy for medically inoperable non‑small cell lung cancer

Stereotactic body radiation therapy (SBRT) is widely used to treat inoperable non‑small cell lung cancer (NSCLC). The present study analyzed the long‑term (10‑year) survival outcomes of patients with NSCLC treated with SBRT in a real‑world setting. Patients with NSCLC treated with SBRT between 2009 and 2013 were retrospectively identified from institutional databases at the Department of Radiation Oncology, University Hospital Halle (Saale) [Halle (Saale), Germany]. Comorbidities were assessed using the Charlson comorbidity index (CCI) and the age‑adjusted CCI. Kaplan‑Meier curves were generated to estimate overall survival (OS) and group comparisons were performed using the log‑rank test. Prognostic factors including age, sex, Karnofsky performance status (KPS), histological subtype, tumor grading, T‑ and N‑stage, PET‑based treatment planning, mean biologically effective dose (BEDmean/Gy10), gross tumor volume (GTV) and CCI were analyzed. Cox proportional hazards regression was used to estimate hazard ratios (HR) and 95% confidence intervals (CI). Variables that were significant in the univariate analysis were entered into a multivariate stepwise regression model. A sensitivity analysis with multiple imputations was performed to assess the robustness of the findings. P<0.05 was considered to indicate a statistically significant difference. A total of 58 patients with NSCLC with M0‑status were included in the present analysis. The 3‑, 5‑ and 10‑year OS rates were 35.09, 24.56 and 8.77%, respectively. The median OS was 32 months (95% CI, 10‑35). In the univariate Cox regression, age ≥75 years was significantly associated with improved survival (HR, 0.54; 95% CI, 0.31‑0.92; P=0.025), though this effect was not statistically significant in the multivariate model (HR, 0.55; 95% CI, 0.30‑1.01; P=0.057). The KPS (≤70 vs. >70%), sex and the age‑adjusted CCI showed no significant association with OS. BEDmean, dichotomized at 120.31 Gy10, was not significantly associated with OS in the multivariate model (P=0.2), although the Kaplan‑Meier analysis showed a significant survival difference (P=0.011). By contrast, larger GTV (>25.6 cm³) was independently associated with worse survival in both the univariate (HR, 1.01; 95% CI, 1.00‑1.02; P=0.041) and multivariate (HR, 1.01; 95% CI, 1.00‑1.02; P=0.024) analyses. These findings were confirmed in a sensitivity analysis using multiple imputations, supporting the robustness of age and GTV as prognostic factors for NSCLC patients treated with SBRT. SBRT provides moderate long‑term survival in patients with NSCLC. Older patients (≥75 years) showed favorable outcomes. Tumor volume was the strongest prognostic factor, while BEDmean and performance status were not independently associated with survival.