Efficacy and safety of carbon ion radiotherapy for bone sarcomas: a systematic review and meta-analysis

OBJECTIVE: This study aimed to systematically evaluate and conduct a meta-analysis of the efficacy and safety of carbon ion radiotherapy for bone sarcomas. METHODS: We searched for articles using the PubMed, Embase, Cochrane Library, and the Web of Science databases from their inception to January 12, 2022. Two researchers independently screened the literature and extracted data based on the inclusion and exclusion criteria. Statistical analyses were performed using STATA version 14.0. RESULTS: We searched for 4378 candidate articles, of which 12 studies were included in our study according to the inclusion and exclusion criteria. Of the 897 BSs patients who received carbon ion radiotherapy in the studies, 526 patients had chordoma, 255 patients had chondrosarcoma, 112 patients had osteosarcoma, and 4 patients had other sarcomas. The local control rate at 1, 2, 3, 4, 5, and 10 years in these studies were 98.5% (95% confidence interval [CI] = 0.961-1.009, I2 = 0%), 85.8% (95% CI = 0.687-1.030, I2 = 91%), 86% (95% CI = 0.763-0.957, I2 = 85.3%), 91.1% (95% CI = 0.849-0.974), 74.3% (95% CI = 0.666-0.820, I2 = 85.2%), and 64.7% (95% CI = 0.451-0.843, I2 = 95.3%), respectively. The overall survival rate at 1, 2, 3, 4, 5, and 10 years in these studies were 99.9% (95% CI = 0.995-1.004, I2 = 0%), 89.6% (95% CI = 0.811-0.980, I2 = 96.6%), 85% (95% CI = 0.750-0.950, I2 = 89.4%), 92.4% (95% CI = 0.866-0.982), 72.7% (95% CI = 0.609-0.844, I2 = 95.3%), and 72.1% (95% CI = 0.661-0.781, I2 = 46.5%), respectively. Across all studies, the incidence of acute and late toxicities was mainly grade 1 to grade 2, and grade 1 to grade 3, respectively. CONCLUSION: As an advanced radiotherapy, carbon ion radiotherapy is promising for patients with bone sarcomas that are unresectable or residual after incomplete surgery. The data indicated that carbon ion radiotherapy was safe and effective for bone sarcomas, showing promising results for local control, overall survival, and lower acute and late toxicity. PROSPERO REGISTRATION NUMBER: CRD42021258480.