Outcomes of stereotactic ablative radiotherapy for central lung tumours: A systematic review

Background and purpose: Stereotactic ablative radiotherapy (SABR) has improved the survival for medically inoperable patients with peripheral early-stage non-small cell lung cancer (NSCLC). We performed a systematic review of outcomes for central lung tumours. Material and methods: The systematic review was performed following PRISMA guidelines. Survival outcomes were evaluated for central early-stage NSCLC. Local control and toxicity outcomes were evaluated for any centrally-located lung tumour. Results: Twenty publications met the inclusion criteria, reporting outcomes for 563 central lung tumours, including 315 patients with early-stage NSCLC. There was heterogeneity in the planning, prescribing and delivery of SABR and the common toxicity criteria used to define toxicities (versions 2.0-4.0). Tumour location (central versus peripheral) did not impact overall survival. Local control rates were ≥85% when the prescribed biologically equivalent tumour dose was ≥100 Gy. Treatment-related mortality was 2.7% overall, and 1.0% when the biologically equivalent normal tissue dose was ≤210 Gy. Grade 3 or 4 toxicities may be more common following SABR for central tumours, but occurred in less than 9% of patients. Conclusions: Post-SABR survival for early-stage NSCLC is not affected by tumour location. SABR achieves high local control with limited toxicity when appropriate fractionation schedules are used for central tumours.