Stereotactic ablative radiotherapy for central and ultra-central lung tumors

Stereotactic ablative radiotherapy (SABR) has emerged as a standard-of-care treatment for patients with early stage non-small cell lung cancer (NSCLC) who are poor surgical candidates. Current evidence supports the consensus that lung SABR with biologically effective dose (BED) ≥100 Gy leads to high local tumor control, and that the treatment is generally well-tolerated when applied to peripheral lung tumors. However, several studies present conflicting evidence for the treatment of central and ultra-central lung tumors, with some showing superb outcomes and others showing concerning rates of morbidity and mortality. Therefore, treatment of central and especially ultra-central lung tumors with SABR remains controversial. In this review, we aim to present the existing evidence for SABR treatment of central and ultra-central lung tumors and delineate the factors that could lead to significant toxicity.