Efficacy and safety of particle therapy for inoperable stage II-III non-small cell lung cancer: a systematic review and meta-analysis.

BACKGROUND AND PURPOSE: Particle therapy, mainly including carbon-ion radiotherapy (CIRT) and proton beam therapy (PBT), has dose distribution advantages compared to photon radiotherapy. It has been widely reported as a promising treatment method for early non-small cell lung cancer (NSCLC). However, its application in locally advanced non-small cell lung cancer (LA-NSCLC) is relatively rare, and its efficacy and safety are inconclusive. This study aimed to provide systematic evidence for evaluating the efficacy and safety of particle therapy for inoperable LA-NSCLC. METHODS: To retrieve published literature, a systematic search was conducted in PubMed, Web of Science, Embase, and Cochrane Library until September 4, 2022. The primary endpoints were local control (LC) rate, overall survival (OS) rate, and progression-free survival (PFS) rate at 2 and 5 years. The secondary endpoint was treatment-related toxicity. The pooled clinical outcomes and 95% confidence intervals (CIs) were calculated by using STATA 15.1. RESULTS: Nineteen eligible studies with a total sample size of 851 patients were included. The pooled data demonstrated that the OS, PFS, and LC rates at 2 years of LA-NSCLC treated by particle therapy were 61.3% (95% CI = 54.7-68.7%), 37.9% (95% CI = 33.8-42.6%) and 82.2% (95% CI = 78.7-85.9%), respectively. The pooled 5-year OS, PFS, and LC rates were 41.3% (95% CI = 27.1-63.1%), 25.3% (95% CI = 16.3-39.4%), and 61.5% (95% CI = 50.7-74.6%), respectively. Subgroup analysis stratified by treatment type showed that the concurrent chemoradiotherapy (CCRT, PBT combined with concurrent chemotherapy) group had better survival benefits than the PBT and CIRT groups. The incidence rates of grade 3/4 esophagitis, dermatitis, and pneumonia in LA-NSCLC patients after particle therapy were 2.6% (95% CI = 0.4-6.0%), 2.6% (95% CI = 0.5-5.7%) and 3.4% (95% CI = 1.4-6.0%), respectively. CONCLUSIONS: Particle therapy demonstrated promising efficacy and acceptable toxicity in LA-NSCLC patients.