Risk-adapted stereotactic ablative radiotherapy for central and ultra-central lung tumours

Abstract

BackgroundSABR is a widely accepted treatment for early-stage lung cancer but there are safety concerns for central and ultra-central tumours. Herein we report our experience using risk-adapted fractionation (prescribed doses: 40–60 Gy in 3–8 fractions) with prioritization of dose to organs at risk. MethodsPatient declining or unsuitable for surgery with primitive or recurrent lung cancer were included. Tumours inside a 2 cm area around proximal bronchial tree (PBT) were classified as central while tumours with PTV overlapping PBT, oesophagus, great vessels and pericardial pleura were classified as ultra-central. We assessed overall survival (OS), disease-free survival (DFS), local control (LC) and toxicities. ResultsFrom 2009 to 2016, 137 patients were treated (median age: 75 years), with 60 central and 77 ultra-central tumours. Median follow-up was 36 months. Median tumour size, GTV and PTV were 2.5 cm (0.9–7), 7.8 cm3 (0.7–94.2) and 30.6 cm3 (6.5–274.3), respectively. For the whole population, median OS and DFS were 46 months and 33 months. One- and 2-years LC rates were 95% and 81%. Median OS between central and ultra-central tumours was statistically different with 57 vs 37 months (HR 0.48, p = 0.017), but LC was not different among them. We observed 4 Grade 3 and 6 Grade 5 toxicities (no grade 4). ConclusionsSABR for central and ultra-central tumours is associated with good OS, DFS and LC rates, with 7.3% grade 3–5 toxicities. Central tumours had a better prognosis in our cohort.