Neoadjuvant SHR-1701 Plus Chemoradiotherapy for Locally Advanced Rectal Cancer

1. Induction Phase SHR-1701: Intravenous infusion at a fixed dose of 30 mg/kg, depending on the protocol), administered on Day 1. CAPOX Regimen: Oxaliplatin: 130 mg/m², intravenous infusion on Day 1; Capecitabine: 1000 mg/m², orally twice daily from Day 1 to Day 14, followed by 7 days of rest. This phase consists of 1 cycle (each cycle is 21 days). 2. Radiotherapy Short-course radiotherapy (SCRT) will be initiated shortly after the induction phase: Total dose: 25 Gy delivered in 5 fractions of 5 Gy each, administered on 5 consecutive days . 3. Consolidation Phase Following radiotherapy, participants will continue treatment with SHR-1701 combined with CAPOX: SHR-1701: Same dose as induction, administered every 3 weeks (Day 1 of each cycle). CAPOX: Same regimen as induction, administered every 3 weeks. This phase consists of 5 cycles (each cycle is 21 days). 4. Surgery After completion of the consolidation phase, total mesorectal excision (TME) will be performed based on investigator assessment and surgical indications. Surgery is typically scheduled within 4 to 8 weeks after completion of consolidation therapy to allow adequate tumor regression and patient recovery.