Long-term outcomes in patients with central and ultracentral non-small cell lung cancer treated with stereotactic body radiotherapy: single-institution experience.

Objective: Treatment-related toxicity following stereotactic ablative radiotherapy (SABR) in patients with central and ultracentral non-small cell lung cancer (NSCLC) is of potential concern, and the best regimens are still being explored. This study aimed to evaluate the clinical outcomes and toxicities of the patients with ultracentral and central NSCLC treated with SABR at our institution.
Method: This retrospective study included patients with central and ultracentral NSCLC treated with SABR to prescription doses of 50 Gy in five fractions, 56 Gy in seven fractions, or 60 Gy in ten fractionsat Jiangsu Cancer Hospital between May 2013 and October 2018. The patients were grouped as central or ultracentral tumors.Overall survival (OS), progression-free survival (PFS), and grade ≥3 toxicities were analyzed.
Results: Forty patients (31 male, nine female) were included. Median follow-up was 41 (5-81) months. The 1-, 2-, and 3-year OS rates were 90.0%, 83.6%, and 66.0%, respectively, and the 1-, 2-, and 3-year PFS rates were 82.5%, 62.9%, and 54.2%, respectively. OS in the ultracentral group was inferior compared with the central group (median, 52.0 months, 95%CI: 43.0-61.0 vs. not reached, P=0.03).The median PFS was 38.0 months in the ultracentral group (95%CI: 19.8-56.2) vs. not reached in the central group, although this difference was not statistically significant (P= 0.06). The overall incidence of grade ≥3 toxicity was five (12.5%) patients, (5 in the ultracentralgroup vs. 0 in the central group; P=0. 11), including one patient with grade 3 pneumonitis, two with grade 3 bronchial obstruction, one with grade 5 bronchial obstruction, and one with grade 5 esophageal perforation.
Conclusion: Worse outcomes were obseverd in patients with ultracentral NSCLC than those with central tumors after SABR. Higher rate of treatment-related grade 3 or more toxicity was observed in the ultracentral group.
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