Outcome and safety of SBRT in centrally and ultra-centrally located lung tumours: A PRISMA-based systematic review and Meta-Analysis

Introduction: Stereotactic Body Radiation Therapy (SBRT) offers a curative treatment option for patients with early-stage central and ultra-central lung tumours, however can be associated with severe side effects.This review provides a structured quantitative evaluation of outcomes and safety in these critical locations, therefore offering safetyoriented evidence to support individualised treatment planning.Methods: Pubmed/MEDLINE was searched with the term "Carcinoma, Non-Small-Cell Lung"[Mesh AND ("Radiosurgery"Mesh OR "SABR" OR "stereotactic ablative radiotherapy" OR "SBRT" OR "stereotactic body radiotherapy")] according to PRISMAguidelines.Trials reporting on SBRT in central and ultra-central lung tumours and on outcome parameters were included.A meta-analysis of proportions was performed using random-effect models.Results: 57 retrospective and 12 prospective trials were included, encompassing in total 3,672 and 1,509 patients with central and ultra-central lung tumours.The median follow-up was 22.7 (range: 10.6 -93.6) months for centrally and 21.2 (8.6 -93.6) months for ultra-centrally located tumours.For ultra-central lesions the median overall survival was 28.0 (12.0 -64.5) months compared to 39.4 (19.0 -57.0) months in central lesions with highest efficacy of SBRT with 60 Gy in 8 fractions.Overall, pooled grade 3-5 toxicity was low for both localizations.The most frequently reported fatal complication in ultra-centrally vs. centrally located tumours was haemorrhage with an estimated proportion of 0.48% range: 0 -14.89;CI 95% = 0.00 -1.68 vs. 0.12% range: 0 -7.09;CI 95% = 0.00 -0.46. Conclusion:SBRT with 60 Gy in 8 fractions provides a feasible and safe curative treatment approach for patients with centrally and ultra-centrally located lung tumours.