Stereotactic body radiation therapy for ultra-central lung malignancies: an updated systematic review and meta-analysis

Abstract Purpose Stereotactic body radiotherapy (SBRT) is a highly effective and well-tolerated treatment modality for peripherally located early-stage non-small cell lung cancer as well as pulmonary metastases. However, its feasibility and safety remain uncertain in patients with ultra-central (UC) lung tumors. This study aims to evaluate the efficacy and safety of SBRT in the management of UC lung malignancies. Methods A systematic review of the available literature was conducted in accordance with the PRISMA guidelines, incorporating studies that reported both treatment-related side effects and therapeutic efficacy associated with SBRT for UC lung malignancies. Patient characteristics, prescription doses, local control (LC), overall survival (OS), and side effects information were extracted. Clinical outcomes were analyzed using the random-effects model. Meta-regression was conducted to determine the effect of various covariates on LC and OS outcomes. Results Twenty-three articles with a total of 1,105 patients were included. Pooled 1- and 2-year LC rates were 93% (95% CI: 88–96%) and 84% (95% CI: 77–89%), respectively. Meta-regression demonstrated a significantly positive association between BED 10 and 1- and 2-year LC rates ( P = 0.001, P < 0.001, respectively), and a significantly negative association between PTV volume and 1- and 2-year LC ( P = 0.048, P = 0.030, respectively). Pooled 1- and 2-year OS rates were 81% (95% CI: 77–85%) and 58% (95% CI: 52–64%), respectively. Meta-regression revealed a significantly positive association between BED 10 and 1- and 2-year OS rates ( P = 0.025, P = 0.002, respectively), and a significantly negative association between PTV volume and 1- and 2-year OS ( P = 0.031, P < 0.001, respectively). The pooled rates of grade ≥ 3 and grade 5 treatment-related side effects were 9% (95% CI: 6–14%) and 2% (95% CI: 1–5%), respectively. Conclusion This meta-analysis demonstrates that SBRT achieves favorable LC rates and is a relatively safe treatment for UC lung malignancies. Although the pooled rate of grade 5 side effects, at 2%, was within an acceptable range, vigilance remains essential. Further prospective research is warranted to verify our conclusions.