Safety and Efficacy of Stereotactic Body Radiotherapy for Centrally Located Early-Stage Non-small Cell Lung Cancer

Stereotactic body radiotherapy (SBRT) is widely practiced in the management of peripheral early-stage non-small cell lung cancer (NSCLC); however, its utility for central tumors is controversial due to the risk of damaging major mediastinal organs. This study evaluates safety and tumor control for centrally located early NSCLC using a moderately hypofractionated SBRT protocol.

Between January 2019 and December 2023, 41 patients with central NSCLC who were deemed unfit or declined surgery (T1-T2a N0 M0, tumor diameter ≤ 4 cm) were treated with SBRT (8 Gy × 8 fractions; total dose 64 Gy, BED₁₀ = 115.2 Gy). Central tumors were defined as lesions within 2 cm of the proximal bronchial tree or abutting mediastinal structures. The key outcome was freedom from local progression (FFLP) at three years. Secondary outcomes were regional recurrence-free survival (RRFS), distant recurrence-free survival (DRFS), overall survival (OS), and treatment-related adverse events.

The median age was 69.0 years (range: 40-89 years); 65.9% were male. Median tumor diameter was 2.5 cm, and 65.9% measured 2-4 cm. The three-year FFLP was 85.9% (95% CI: 66.1%-94.5%). Three-year OS, RRFS, and DRFS were 68.6% (95% CI: 48.7%-82.1%), 76.8% (95% CI: 56.6%-88.5%), and 83.6% (95% CI: 66.8%-92.3%), respectively. Local failure occurred in four (9.8%), regional failure in nine (22.0%), and distant failure in eight (19.5%) patients. Treatment-related toxicity was minimal (grade ≥ 2 occurrences in 1 patient (2.4%) and no grade ≥ 3 toxicity).

A dose of 64 Gy delivered in eight fractions through SBRT exerts good local control and low toxicity for centrally located early-stage NSCLC. This hypofractionated regimen seems to be safe and effective for patients who refuse or are unsuitable for surgery and comparable to results achieved with surgery.