Neoadjuvant immunotherapy has achieved exciting efficacy with high clinical complete response (cCR) and pathologic complete response (pCR) rates and durable long-term effects. PD-1 checkpoint blockade-based immunotherapy has been highly successful in microsatellite instability high (MSI-H)/mismatch repair deficiency (dMMR) colorectal cancer and has been recommended as the first-line treatment for metastatic colorectal cancer by domestic and international guidelines. Several studies have shown that immunotherapy can be a potentially curable treatment for MSI-H rectal cancer and has even shown promise in organ preservation in colon cancer. In this study, we first clarified the feasibility of the watch-and-wait strategy after PD-1 checkpoint blockade treatment by indirect and direct evidence. Then from the assessment tools (including digital rectal examination, endoscopy, radiology, and lymph node assessment), the viable assessment methods of cCR for immunotherapy and related difficulties are proposed. Finally, the medication choices of immunotherapy, the treatment regimen, and the follow-up strategy are further discussed. We hope that neoadjuvant immunotherapy could be appropriately applied in MSI-H/dMMR colorectal cancer so that more patients can achieve organ preservation.
新辅助免疫治疗具有高临床完全缓解（cCR）率和病理完全缓解（pCR）率，而且疗效持久。基于 PD-1 抗体的免疫治疗在微卫星高度不稳定（MSI-H）/错配修复缺失（dMMR）结直肠癌中取得了巨大成功，已被国内外多项指南推荐为局部进展期结直肠癌的一线疗法。多项研究显示，免疫治疗可作为MSI-H直肠癌的潜在治愈手段，甚至在结肠癌器官保留中也展示出良好前景。本文通过间接和直接证据阐明了PD-1 抗体治疗后等待观察的可行性，然后从评估手段出发（包括直肠指检、内镜、影像学和淋巴结评估），提出免疫治疗cCR可供选择的评估方法及存在的困难，并讨论了免疫治疗的药物选择、治疗周期以及随访策略。希望新辅助免疫治疗能在 MSI-H/dMMR结直肠癌中得到恰当的应用，使更多的患者器官得到保留。.