Laterality-Dependent Outcomes of Stereotactic Body Radiotherapy for Peripheral Pulmonary Lesions: A Retrospective Single-Institution Study

Background Stereotactic body radiotherapy (SBRT/SABR) is a curative treatment for early-lung cancer in patients unsuitable for surgery. While tumor laterality is routinely considered in surgical decision-making, its prognostic relevance in patients treated with SBRT remains unclear. This study evaluated clinical outcomes after SBRT and assessed the prognostic impact of tumor laterality. Materials and methods This single-institution retrospective study included consecutive patients treated with SBRT for peripheral pulmonary lesions between 2011 and 2024. Prescribed ablative doses corresponded to a median BED₁₀ > 100 Gy. Local recurrence (LR), loco-regional recurrence (LRR), distant metastases (DM), and cancer-specific death (CSD) were analyzed using competing-risk models; progression-free survival (PFS) and overall survival (OS) using Kaplan–Meier method. Results A total of 115 patients (median age 75 years) were treated with SBRT. The most common regimens were 42–54 Gy in three or 50–55 Gy in five fractions (median BED₁₀=116 Gy). Toxicities were mild and transient. At a median follow-up of 39 months, 5-year OS and PFS were 55% and 39%, with a 5-year cumulative incidence of LR of 7.1%. Left-sided tumors showed worse outcomes, including shorter OS (HR = 2.96, p < 0.001), PFS (HR = 3.30, p < 0.001), higher LRR (HR = 3.60, p = 0.015), and CSD (HR = 3.96, p = 0.003). Tumor laterality remained an independent prognostic factor in multivariable analysis. Conclusions SBRT achieved excellent local control and favorable safety outcomes. Tumor laterality emerged as an independent prognostic factor, with left-sided lesions associated with inferior outcomes. These findings suggest that laterality may represent a simple, clinically relevant factor for risk stratification and post-treatment surveillance of patients undergoing SBRT.