Stereotactic ablative radiotherapy of 60 Gy in eight fractions is safe for ultracentral non-small cell lung cancer

Background There is no consensus on the definition or recommended radiotherapy treatment of ultracentral non-small cell lung cancer (NSCLC). Here, we report our institution's experience in treating ultracentral lung cancer patients with stereotactic ablative radiotherapy (SABR) of 60 Gy in eight fractions. Methods We retrospectively reviewed the outcomes of 21 ultracentral NSCLC patients treated with 60 Gy SABR in eight fractions. We defined ultracentral lung cancer as the planning target volume (PTV) directly abutting or overlapping central structures, including the proximal bronchial tree, heart, and great vessels but not the esophagus. The Kaplan-Meier method was used to estimate overall survival (OS), progression-free survival (PFS) and local control (LC). Toxicity was scored per the CTCAE v4.03. Results The median follow-up time was 15 months, and the median OS was 15 months. The one- and two-year OS rates were 87.5% and 76.6%, respectively. The one- and two-year PFS rates were 71.1% and 64.0%, respectively. The one- and two-year LC rates were 92.9% and 92.9%, respectively. The rate of grade 2 treatment-related toxicities was 19.1%. There was no grade >= 3 treatment-related toxicity. Conclusion SABR of 60 Gy in eight fractions is feasible for ultracentral NSCLC.