Radical Concurrent Chemoradiotherapy With DDP/5-FU and PD-1 Antibody for Non-metastatic Rectal Squamous Cell Carcinoma

Chemotherapy (/3w): 1)DDP 75 mg/m2, d1, intravenous infusion; 2)5-FU 1000 mg/m2, d1-4, continuous pumping intravenously; Immunotherapy (/3w): PD-1 monoclonal antibody(sintilimab) 200mg, d1, intravenous infusion; Radiotherapy (at 3rd week after first time of chemotherapy):Daily single dose of 2Gy, with a total dose of 50-54GY.