Neoadjuvant Moderately Hypofractionated Radiotherapy Combined with Chemotherapy and Immunotherapy for High-risk LARC

35 Gy in 10 fractions to mesorectal and metastatic lymph nodes, and 30 Gy in 10 fractions to pelvic lymphatic drainage area, weekly over 5 days at 3-3.5 Gy/day.

CapeOx-Capecitabine 1000 mg/m² orally twice daily (days 1-14, every 21 days) + Oxaliplatin 130 mg/m² IV (day 1, every 21 days).

Serplulimab 300 mg IV infusion on day 1 every 21 days.

Total mesorectal excision (TME) surgery assessment post 3 cycles of chemotherapy and immunotherapy; eligible patients undergo TME surgery.