Comparative analysis between induction chemotherapy combined with concurrent chemoradiotherapy and chemoradiotherapy alone for thoracic esophageal squamous cell carcinoma

Abstract

Objective To compare the clinical efficacy and safety between induction chemotherapy (IC) followed by concurrent chemotherapy (CRT) and CRT alone in patients with inoperable thoracic esophageal squamous cell carcinoma (ESCC). Methods Between 2002 and 2015, clinical data of 267 thoracic ESCC patients undergoing definitive CRT based on docetaxel combined with cisplatin were retrospectively analyzed. Through a matched case-control study, 85 patients receiving IC combined with CRT were matched to those undergoing CRT alone at a ratio of 1vs.1, according to age, gender, performance status, tumor location, tumor length, and TNM staging as the matching factors. Clinical efficacy and safety between two groups were statistically compared. Kaplan-Meier survival analysis was used to analyze the survival. The log-rank test was adopted to examine within-group differences. The Cox regression model was used for multivariate analysis. Results The median follow-up time for 170 patients was 18 months (range, 3-72 months). The overall objective response rates in the IC and CRT groups were 74.1% and 58.8%(P=0.035). The 3-year overall survival (OS) and progress-free survival (PFS) rates in the IC group were 44.2% and 34.8%, significantly higher than 29.7% and 15.4% in the CRT group (P=0.028, P=0.015). Subgroup analysis revealed that patients responsive to IC obtained significantly better OS (P=0.002), PFS (P=0.001), and local recurrence-free survival (LRFS)(P=0.002) compared with the IC non-responder, whereas the distant metastasis-free survival (DMFS) did not significantly differ (P=0.166). The incidence rate of grade 3–4 leukopenia in the IC group was significantly higher than that in the CRT group (38.8% vs. 24.7%, P=0.048). Multivariate analysis revealed that age and the addition of IC were independent prognostic factors for OS (P=0.003, 0.016). Conclusions Compared with concurrent CRT, IC in combination with CRT can yield better short-term efficacy and longer survival for ESCC patients. The risk of hematological toxicity in the IC group is relatively higher but tolerable. Prospective randomized trials are required to confirm the clinical efficacy and safety of IC for thoracic ESCC patients. Key words: Esophageal neoplasms/concurrent chemoradiotherapy; Induction chemotherapy; Prognosis