Sintilimab After Concurrent Chemoradiotherapy in Elderly Patients With Esophageal Squamous Cell Carcinoma

This trial is a prospective, randomized, controlled, multicenter, phase II clinical study to evaluate the efficacy and safety of sintilimab as consolidation therapy in elderly patients with esophageal cancer who did not progress after concurrent chemoradiotherapy. Patients aged 70-85 years with esophageal squamous cell carcinoma who did not progress after concurrent chemoradiotherapy and meet the inclusion criteria will be stratified according to MRD status (positive vs negative) and randomized in a 1:1 ratio into two groups: the treatment group receiving sintilimab (for patients with a weight \<60 kg: 3 mg/kg IV on Day 1 every 3 weeks; for patients with a weight ≥60 kg: 200 mg IV on Day 1 every 3 weeks) and the observation group receiving regular follow-up. Patients should receive the first dose within 42 days after completing the last radiotherapy session and continue treatment until disease progression, intolerable toxicity, loss to follow-up, death, or other circumstances where the investigator determines treatment should be discontinued, whichever occurs first. The maximum duration of sintilimab treatment is 12 months (from the start of treatment), while the observation group will be followed up every 3 months for at least one year. No other anti-tumor treatments are allowed during the study period. The study aims to compare the effects of the two treatment modalities on progression-free survival, overall survival, tumor response, toxicity reactions, and quality of life in elderly patients with esophageal cancer.