Background: SABR 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.
Methods: Patient 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.
Results: From 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).
Conclusions: SABR 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.
Keywords: Central Tumours; Non-small-cell lung cancer; Stereotactic ablative radiotherapy; Stereotactic body radiation therapy; Toxicity.
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