Induction immunochemotherapy followed by radiotherapy for patients with unresectable locally advanced or metastatic esophageal cancer: A propensity score-matched analysis

Background: The study aimed to investigate the efficacy of induction immunochemotherapy before radiotherapy (RT) for patients with locally advanced or metastatic esophageal cancer.Methods: Patients with unresectable locally advanced or metastatic esophageal cancer who received induction immunochemotherapy followed by RT (ICIs + RT group) and RT alone (RT group) were retrospectively identified in two cancer centers, respectively. Propensity score matching (PSM) was used to balance the potential con-founders between the two groups. Overall survival (OS), progression-free survival (PFS), and recurrence patterns were evaluated.Results: A total of 467 patients were reviewed, and 66 were matched in each group. After PSM, the 1-and 2-year OS rates were 84.6% and 57.9% in ICIs + RT group, and 71.1% and 43.0% in RT group (HR 0.60, 95% CI 0.36-1.00, p = 0.050). The absolute increase of restricted mean survival time (RMST) for OS in ICIs + RT group compared with RT group were 0.89 years (p = 0.023) at one year and 2.59 years at two years (p = 0.030). The median PFS time, 1-and 2-year PFS rates were 20.3 months, 69.3%, and 45.7% in ICIs + RT group, and 12.2 months, 51.4%, and 35.8% in RT group (HR 0.64, 95% CI 0.41-0.99, p = 0.045). The cumulative locoregional recurrence (LRR) rate was significantly lower in ICIs + RT group (1-year rate, 17.4% vs. 38.8%, p = 0.011), and distant metastasis (DM) rates were comparable (p = 0.755). Consolidation ICIs was associated with a trend of improved 1-year OS and PFS.Conclusion: Induction immunochemotherapy followed by RT might improve locoregional control and survival outcomes for patients with unresectable locally advanced or metastatic esophageal cancer.