Clinical observation of anti-PD-1/PD-L1 immunotherapy plus concurrent chemoradiotherapy for locally advanced esophageal squamous cell carcinoma.

[OBJECTIVE] This study analyzed the efficacy of the PD-1 inhibitor Sintilimab combined with concurrent chemoradiotherapy (CCRT) in patients with unresectable locally advanced esophageal squamous cell carcinoma (ESCC).

[METHODS] A retrospective study involved 177 individuals with unresectable advanced ESCC, treated with anti-PD-1/PD-L1 immunotherapy combined with CCRT. Patients were categorized into three groups: combined positive score (CPS) ≥ 50, 1 < CPS < 50, and CPS < 1. Clinical data and laboratory markers (carcinoembryonic antigen [CEA] and squamous cell carcinoma antigen [SCC-Ag]) were collected at baseline, 6, 12, and 24 months. PET/CT and CT scans assessed tumor response, ORR, and DCR. Kaplan-Meier curves analyzed the impact of CPS scores on progression-free survival (PFS) and overall survival (OS). Baseline data were matched at a 1:1 ratio by propensity score matching, followed by Cox regression analyses.

[RESULTS] No noticeable differences were present among the groups regarding gender, tumor location, prior chemotherapy, prior radiotherapy, or laboratory markers. After treatment, CEA and SCC-Ag levels significantly decreased, with the lowest levels observed at 24 months post-treatment. Higher CPS scores were associated with reduced CEA and SCC-Ag levels. PD-L1-positive groups (CPS > 1) had higher ORR and DCR than the PD-L1-negative group. As CPS scores increased, PFS and OS were significantly prolonged. Serum fibrinogen, CEA and SCC-Ag were identified as independent risk factors for OS; Serum CEA and SCC-Ag were independent risk factors affecting PFS.

[CONCLUSION] Higher CPS scores are associated with improved PFS and OS in patients with locally advanced ESCC receiving anti-PD-1/PD-L1 immunotherapy combined with CCRT.