Induction Immunochemotherapy Yields a Higher Conversion Rate and Better Overall Survival than Chemotherapy in Initially Unresectable Esophageal Squamous Cell Carcinoma.

Introduction: This study compared the surgical conversion rate and overall survival (OS) between induction chemotherapy (iC) and induction immunochemotherapy (iIC) for patients with initially unresectable esophageal squamous cell carcinoma (iuESCC).

Methods: In this multicenter, retrospective cohort study, patients from four high-volume institutions with unresectable diseases were included. The primary endpoints were the conversion surgery rate and OS. A multivariate Cox regression analysis was used to identify the independent significant prognostic factors associated with OS. The stabilized inverse probability of treatment weighting was applied to confirm the survival comparison between the iIC and iC cohorts.

Results: A total of 309 patients (150 in the iIC cohort and 159 in the iC cohort) were included. A significantly higher conversion surgical rate was observed in the iIC cohort (iIC vs. iC: 127/150, 84.7% vs. 79/159, 49.7%, P < 0.001). The pathological complete response rates were 22.0% and 5.1% in the iIC and the iC cohorts, respectively (P = 0.001). A significant difference in the OS was observed between the iIC (not reached) and iC cohorts (median 95% CI 36.3 [range 27.2-45.5]). The stabilized inverse probability of treatment weighting yielded similar results. Regimen (iIC vs. iC, HR 0.215, 95% CI 0.102-0.454, P < 0.001) and operation (yes vs. no, HR 0.262, 95% CI 0.161-0.427, P < 0.001) were the significant prognostic factors for OS.

Conclusions: Immunochemotherapy plus conversion surgery in the induction setting may be a better treatment option to achieve high pathological responses and improve OS in iuESCC patients.