Five-year follow-up after stereotactic body radiotherapy for medically inoperable early-stage non-small cell lung cancer: a multicenter study

Background: Stereotactic body radiotherapy (SBRT) has proven to provide high rates of tumor control for patients with early-stage non-small cell lung cancer (NSCLC). We are reporting a multicenter experience of long-term clinical outcomes and adverse effect profiles of patients with medically inoperable early-stage NSCLC treated with SBRT. Methods: A total of 145 early-stage NSCLC patients underwent SBRT at the Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Shandong Cancer Hospital and Institute, and Shanghai Pulmonary Hospital between October 2012 and March 2019. Four-dimensional computed tomography (4D-CT) simulation was used for all patients. All received a biologically effective dose (BED; alpha/beta=10) of 96-120 Gy with the prescribed isodose line covering >95% of the planning target volume (PTV). Survival was analyzed by the Kaplan-Meier method. Survival was estimated using the Kaplan-Meier method. Results: The median tumor diameter was 2.2 (range, 0.5-5.2) cm. The median follow-up was of 65.6 months. Thirty-five patients (24.1%) developed disease recurrence. The rates of local, regional, and distant disease recurrence were, respectively, 5.1%, 7.4%, and 13.2% at 3 years; and 9.6%, 9.8%, and 15.8% at 5 years. Progression-free survival (PFS) rates at 3 and 5 years were 69.2% and 60.5% respectively; the overall survival (OS) rates were 78.1% and 70.1%, respectively. Five patients (3.4%) experienced grade 3 treatment-related adverse events (AEs). No patient experienced grade 4 or 5 toxicity. Conclusions: From our retrospective analysis with long-term follow-up in Chinese population, SBRT achieved high rate of local control (LC) and low toxicity in patients with early-stage NSCLC. This study offered robust long-term outcome data of SBRT in the Chinese population, which was very rarely reported in China before.