Fig. 1: The flowchart of trial and schedules of treatments.

A Study flowchart.* The two dMMR/MSI-H patients were excluded from the study. One had lung metastasis at the baseline, and another had a history of breast cancer within the past 5 years. B Study design. Patients with T3–4N0M0 or T1–4N+M0 received 6 cycles of mFOLFOX6 and long course radiotherapy (50 Gy/25f, 2 Gy/f, 5 days/week) followed by surgery. Sintilimab (3 mg/kg, iv.gtt, 2nd–6th cycle) was added during chemoradiotherapy.