[Neoadjuvant immunotherapy for colorectal cancer].

Immunotherapy has been one of the hot topics in the field of colorectal cancer research in recent years. Patients with microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) are the main beneficiaries of immunotherapy. The response rate of patients with dMMR/MSI-H colorectal cancer receiving neoadjuvant immunotherapy is nearly 100%, of which the pathological complete response rate approximately accounts for 60%-67%. The prospect of neoadjuvant immunotherapy in dMMR or MSI-H colorectal cancer patients, especially in the rectal cancer patients, lies in achieving sustainable clinical complete response so as to achieve organ preservation and avoid adverse effects on reproductive, sexual, bowel and bladder function after surgery and radiotherapy. Studies have shown that part of the colorectal cancer patients of microsatellite stability (MSS) or mismatch repair proficient (pMMR) can respond to neoadjuvant immunotherapy in combination with other treatment methods such as radiotherapy and chemotherapy. In pMMR or MSS colorectal cancer, optimizing neoadjuvant immunotherapy regimens and finding effective efficacy prediction biomarkers are important research directions. In neoadjuvant immunotherapy, overcoming primary and secondary resistance and identifying the pseudoprogression and hyperprogression of neoadjuvant immunotherapy are clinical challenges that require attention. This paper comprehensively reviews the research progress, controversies,challenges and future research directions of neoadjuvant immunotherapy (mainly immune checkpoint inhibitors) in colorectal cancer.免疫治疗是近年来在结直肠癌领域研究的热点之一。错配修复基因缺陷（dMMR）或微卫星高度不稳定（MSI-H）的结直肠癌患者是免疫治疗的主要获益人群。dMMR或MSI-H结直肠癌患者接受新辅助免疫治疗的缓解率接近100%，其中病理学完全缓解率为60%~67%。新辅助免疫治疗在dMMR或 MSI-H结直肠癌，尤其是直肠癌人群的应用前景，在于可获得持续临床完全缓解，以达到器官保留和避免手术以及放疗后对生育能力、性功能、肠道和膀胱功能产生的不良影响。研究表明，部分错配修复基因正常（pMMR）或微卫星稳定（MSS）的结直肠癌患者联合其他治疗手段如放疗、化疗等对新辅助免疫治疗可产生应答。在 pMMR或MSS结直肠癌中，优化新辅助免疫治疗方案和寻找有效的疗效预测生物标志物是重要的研究方向。在新辅助免疫治疗中，克服原发和继发性耐药、甄别新辅助免疫治疗的假性进展和超进展是需要关注的临床挑战。本文就新辅助免疫治疗（主要是免疫检查点抑制剂）在结直肠癌中的研究进展、面临的争议与挑战以及未来探索的方向进行了全面的评述，期望为结直肠癌新辅助免疫治疗的发展提供研究思路。.