An Observational Study on the Safety and Efficacy of Immunotherapy Combined With Concurrent Chemoradiotherapy in Elderly Patients With Esophageal Squamous Cell Carcinoma

"Patients will receive concurrent chemoradiotherapy (CCRT) combined with immunotherapy. The treatment includes:~Radiotherapy: Individualized radiotherapy targeting the tumor. Concurrent Chemotherapy: Platinum-based doublet chemotherapy (e.g., cisplatin + fluorouracil or S-1) administered during radiotherapy.~Immunotherapy: PD-1 inhibitor (e.g., tislelizumab) used to enhance the immune response against cancer cells.~The treatment will be tailored to each patient's condition, with regular follow-up assessments every 3 months for up to 2 years to monitor efficacy and safety."