Clinical outcomes of stereotactic body radiotherapy for de novo pulmonary tumors in patients with completely resected early stage non-small cell lung cancer

Qianqian Zhao, Gang Chen, Luxi Ye, Zhaochong Zeng, Shiming Shi, Jian He Department of Radiation Oncology, Zhongshan Hospital, Fudan University, Shanghai, China Purpose: Following surgery for early stage non-small-cell lung cancer (NSCLC), de novo pulmonary tumors are common. This study aimed to assess the efficacy, patterns of failure, and toxicity of stereotactic body radiotherapy (SBRT) in the treatment of de novo pulmonary tumors following curative resection of early stage NSCLC.Patients and methods: We reviewed the medical data of patients who had received definitive intent SBRT for small lung cancer at Zhongshan Hospital, Fudan University, between June 2011 and December 2017. Patients who had experienced complete resection for prior early stage NSCLC before SBRT were identified for further analysis. Incidences of locoregional recurrence (LR) and distant metastasis (DM) were evaluated using the alternative cumulative incidence competing risk method. The probability of survival was estimated using the Kaplan–Meier method.Results: A total of 33 patients with 36 lesions were eligible and included in this study. The median follow-up time was 32 months. Estimated incidences of LR and DM were 37.62% and 15.92%, respectively, at 1 year and 48.02% and 21.23%, respectively, at 2 years. The progression-free survival and overall survival of all patients were 62.40% and 90.30%, respectively, at 1 year and 52.00% and 69.90%, respectively, at 2 years. In all, 26 patients experienced grade 1 SBRT-related toxicity, 11 patients experienced grade 2 SBRT-related toxicity, and three patients experienced grade 3 toxicity. There were no grade 4/5 toxicities or SBRT-related deaths during the follow-up period.Conclusion: SBRT appears to be a safe and potentially effective alternative therapeutic option for de novo pulmonary tumors following early stage NSCLC radical resection, despite impaired pulmonary reserve. Keywords: stereotactic body radiotherapy, de novo pulmonary tumors, surgical resection, clinical outcomes