Abstract
BACKGROUND: Esophageal squamous cell carcinoma (ESCC) is a common malignancy in China, often diagnosed at an advanced stage, with poor prognosis. Standard treatments such as definitive chemoradiotherapy offer limited survival benefits. Recent advances in immune checkpoint inhibitors combined with chemotherapy have shown promise, but their effectiveness and safety in conjunction with radiotherapy for unresectable ESCC require further exploration. AIM: To assess the safety and effectiveness of induction chemoimmunotherapy followed by definitive radiotherapy or concurrent chemoradiotherapy (CCRT) in locally advanced unresectable ESCC. METHODS: This retrospective study included 80 patients with locally advanced unresectable ESCC who underwent induction chemoimmunotherapy followed by definitive radiotherapy, recruited from Zhejiang Cancer Hospital. All patients received 2-4 cycles of chemotherapy plus programmed cell death 1/programmed cell death ligand 1 inhibitor, were re-evaluated to be inoperable, then received definitive radiotherapy or CCRT. Primary endpoint was treatment safety and tolerance. SPSS 26.0 software was used for data analysis. Th Kaplan-Meier method was used for survival analysis. RESULTS: Thirty-seven (46.3%) patients received CCRT and 43 (53.7%) received radiotherapy alone. The most common treatment-related adverse events included radiation esophagitis (32/80, 40.0%) and anemia (49/80, 61.3%), with 22 (27.5%) experiencing grade ≥ 3 adverse events. No treatment-related deaths occurred. After median follow-up of 16.5 months, the median progression-free survival (PFS) was 14.2 months, and median overall survival (OS) was 19.9 months. The 1-year and 2-year PFS and OS were 55.8% and 31.6%, and 67.5% and 44.1%, respectively. Patients with partial response had better outcomes than those with stable disease: 1-year PFS 69.4% vs 43.9% (P = 0.011) and OS 83.2% vs 48.8% (P = 0.007). Induction therapy effectiveness and immunotherapy maintenance were independent prognostic factors for OS. CONCLUSION: Chemotherapy combined with programmed cell death 1/programmed cell death ligand 1 inhibitor followed by definitive radiotherapy or CCRT in patients with locally advanced ESCC was safe and effective.