Addition of Induction or Consolidation Chemotherapy in Definitive Concurrent Chemoradiotherapy vs. Concurrent Chemoradiotherapy Alone for Patients With Unresectable Esophageal Cancer: A Systematic Review and Meta-Analysis

Abstract

<h3>Purpose/Objective(s)</h3> Definitive concurrent chemoradiotherapy (CCRT) have become the standard of care in esophageal carcinoma patients who are not surgical candidates. The efficacy of induction chemotherapy (IC) or consolidation chemotherapy (CCT) for unresectable esophageal cancer (EC) treated with CCRT is unclear. We performed a systematic review and meta-analysis of published papers to evaluate the potential benefit of IC or CCT for patients with EC. <h3>Materials/Methods</h3> Eligible studies of IC followed by CCRT (IC-CCRT) versus CCRT alone or CCRT followed by CCT (CCRT-CCT) versus CCRT alone were retrieved through extensive searches of the PubMed, Science Direct, Embase, and Cochrane library databases from the establishment of the database to January 2021. Data such as one-, two-, three- and five-year overall survival (OS), local recurrence rate (LRR) and distant metastasis rate (DMR) were collected for meta-analysis to evaluate the efficacy of IC/CCT. Hazard ratio (HR), odd ratio (OR) and 95% confidence intervals (CI) were calculated. <h3>Results</h3> Three studies of IC-CCRT versus CCRT alone including 726 EC patients and six studies of CCRT-CCT versus CCRT alone including 1268 patients with esophageal squamous cell carcinoma (ESCC) were finally identified in our analysis. Both IC-CCRT group (HR 0.446, 95% CI 0.287-0.694; <i>P</i> < 0.001) and CCRT-CCT group (HR 0.706, 95% CI 0.530-0.941; <i>P</i> = 0.018) exhibited statistically significant improvement in one-year OS rate compared to CCRT alone, while the two-year OS rate of IC-CCRT (HR 0.803, 95% CI 0.589-1.095; <i>P</i> = 0.166) or CCRT-CCT (HR 0.916, 95% CI 0.716-1.171; <i>P</i> = 0.483) was similar with CCRT alone. However, comparing with CCRT alone, CCRT-CCT group had lower DMR (OR 1.562, 95% CI 1.090-2.240; <i>P</i> = 0.015). Besides, no differences were observed between two groups of CCRT-CCT and CCRT alone in three-year OS rate (HR 0.85, 95% CI 0.659-1.096; <i>P</i> = 0.21), five-year OS rate (HR 1.019, 95% CI 0.692-1.499; <i>P</i> = 0.925) and LRR (OR 0.899, 95% CI 0.686-1.179; <i>P</i> = 0.441). <h3>Conclusion</h3> This is the first meta-analysis to compare the effects of IC-CCRT or CCRT-CCT versus CCRT alone. This result revealed the short-time instead of long-time survival benefit of additional IC/CCT compared to CCRT alone for patients with unresectable EC. CCRT-CCT provided significant benefits to reduce the risk of distant-metastasis, and might be fit better in patients with esophageal squamous cell carcinoma (ESCC).