Precision Stereotactic Body Radiotherapy for Ultra‐Central NSCLC: Tailored Margins Reduce Toxicity Without Compromising Tumor Control

ABSTRACT Stereotactic body radiation therapy (SBRT) is effective for early‐stage non‐small cell lung cancer (NSCLC), but the treatment of ultra‐central NSCLC (UCNLC) near critical structures remains challenging. This retrospective study analyzed 66 patients with stage I–II unresectable UCNLC who underwent SBRT at Shanghai Pulmonary Hospital (2020–2023). UCNLC was defined by planning target volumes (PTVs) abutting/overlapping vital structures (proximal bronchial tree, esophagus, heart, great vessels, pulmonary vessels) or internal target volumes (ITVs) within 1 cm of these organs. Tailored SBRT plans with non‐uniform PTV margins were used in 45.5% of cases, enabling 53.3% of patients to receive a biologically effective dose ≥ 100 Gy. With a median follow‐up of 32.2 months, the median progression‐free survival (PFS) was 42.9 months; 1‐ and 3‐year PFS rates were 93.9% and 68.8%, respectively. Median local control (LC) and overall survival (OS) were not reached, with 1‐ and 3‐year LC rates of 98.5% and 84.6%, and OS rates of 98.5% and 88.7%, respectively. Toxicities were predominantly grade 1–2, with only one grade 3 pneumonitis. Larger ITV predicted poorer LC and PFS, whereas T stage independently predicted PFS and OS. Therefore, a non‐uniform PTV strategy maintained clinical efficacy without compromising safety, supporting its application in UCNLC management.