A meta-analysis comparing efficacy and safety between proton beam therapy versus carbon ion radiotherapy

Abstract

Background: This study aimed to compare the outcomes of proton beam therapy (PBT) and carbon ion radiotherapy (CIRT) by a systematic review and meta-analysis of the existing clinical evidence.

Methods: A systematic literature search was performed to identify studies comparing the clinical outcomes of PBT and CIRT. The included studies were required to report oncological outcomes (local control [LC], progression-free survival [PFS], or overall survival [OS]) or adverse events.

Results: Eighteen articles comprising 1857 patients (947 treated with PBT and 910 treated with CIRT) were included in the analysis. The pooled analysis conducted for the overall population yielded average hazard ratios of 0.690 (95% confidence interval (CI), 0.493-0.967, p = 0.031) for LC, 0.952 (95% CI, 0.604-1.500, p = 0.590) for PFS, and 1.183 (0.872-1.607, p = 0.281) for OS with reference to CIRT. The subgroup analyses included patients treated in the head and neck, areas other than the head and neck, and patients with chordomas and chondrosarcomas. These analyses revealed no significant differences in most outcomes, except for LC in the subgroup of patients treated in areas other than the head and neck. Adverse event rates were comparable in both groups, with an odds ratio (OR) of 1.097 (95% CI, 0.744-1.616, p = 0.641). Meta-regression analysis for possible heterogeneity did not demonstrate a significant association between treatment outcomes and the ratio of biologically effective doses between modalities.

Conclusion: This study highlighted the comparability of PBT and CIRT in terms of oncological outcomes and adverse events.

Keywords: carbon ion radiotherapy; meta-analysis; oncologic outcome; particle beam radiotherapy; proton beam therapy; toxicity.

FIGURE 1

PRISMA flow chart of literature search and selection. PICOS, Population, Intervention, Comparison, Outcome, and Study design.

FIGURE 2

Forest plots with random effect model of pooled analyses regarding (A) local control, (B) progression‐free survival, (C) overall survival, and (D) adverse events. AE, adverse event; CI, confidence interval; HR, hazard ratio; LC, local control; OR, odds ratio; OS, overall survival; PFS, progression‐free survival; RE, random effect.