Stereotactic body radiotherapy for early-stage non-small cell lung cancer: Comprehensive analysis of outcomes and recurrence from a single-center experience

This study aimed to analyze prognostic factors in patients with early-stage non-small cell lung cancer (NSCLC) treated with stereotactic body radiotherapy (SBRT), focusing on symptomatic radiation pneumonitis (RP) and treatment failure patterns. This retrospective cohort study included 271 patients with early-stage NSCLC (276 lesions) treated with SBRT from May 2012 to January 2022. SBRT was administered according to standardized protocols with doses ranging from 28.5 to 80 Gy in 1 to 10 fractions. Tumor recurrence, RP, and failure patterns were assessed through imaging and clinical evaluations. Prognostic factors for overall survival (OS) and local control (LC) were identified using Kaplan-Meier survival analysis, Cox models, and logistic regression for RP risk. With a median follow-up of 30.8 months, the 1-, 2- and 3-year OS rates were 96.1, 91.8, and 86.5%, respectively, and LC rates were 98.8, 96.5, and 92.9%, respectively. The Eastern Cooperative Oncology Group performance status (P=0.002) and higher fractional dose (P=0.041) were significant predictors of OS. Larger tumor size (P<0.001) and higher solid-to-total tumor ratio (P=0.028) were associated with increased local recurrence risk. Symptomatic RP (7.2% of lesions) was associated with solid tumor size (P=0.050). Larger tumors with a higher solid component had more in-field recurrences, while marginal recurrences were often attributable to air space spread and pleural involvement. Higher fractional doses in SBRT benefit patients with early-stage NSCLC, especially those with larger tumors or significant solid components, suggesting that dose escalation or more biologically effective therapies could enhance outcomes and optimize SBRT protocols.