SCRT + mFOLFOX6 + PD-1 Antibody + Targeted Therapy for HIgh-Risk pMMR/MSS Rectal Cancer

Patients undergo SCRT at a dose of 5Gy × 5 fractions

Patients complete immune therapy with PD-1 monoclonal antibody for 4 cycles.

Patients complete chemotherapy with mFOLFOX6 regimen for 4 cycles.

Patients with RAS/BRAF wild-type receive targeting therapy with Cetuximab for 4 cycles.

Patients with RAS/BRAF mutations receive targeting therapy with Bevacizumab for 3 cycles. (Bevacizumab is not used in the last cycle of the bevacizumab group)

Surgery either local excition or total mesorectal excision is performed 8-10 weeks after the completion of short-course radiotherapy.