Rectal cancer is a heterogeneous disease with complex genetic and molecular subtypes. Emerging progress of neoadjuvant therapy has led to increased pathological and clinical complete response (cCR) rates for microsatellite stable (MSS) rectal cancer, which responds poorly to immune checkpoint inhibitor alone. As a result, organ preservation of MSS rectal cancer as an alternative to radical surgery has gradually become a feasible option. For patients with cCR or near-cCR after neoadjuvant treatment, organ preservation can be implemented safely with less morbidity. Patient selection can be done either before the neoadjuvant treatment for higher probability or after with careful assessment for a favorable outcome. Those patients who achieved a good clinical response are managed with nonoperative management, organ preservation surgery, or radiation therapy alone followed by strict surveillance. The oncological outcomes of patients with careful selection and organ preservation seem to be noninferior compared with those of radical surgery, with lower postoperative morbidity. However, more studies should be done to seek better regression of tumor and maximize the possibility of organ preservation in MSS rectal cancer.

直肠癌是一种异质性疾病，具有复杂的遗传和分子亚型。新辅助治疗的新兴进展导致微卫星稳定（MSS）直肠癌的病理和临床完全缓解（cCR）率提高，这种疾病对单独的免疫检查点抑制剂的反应较差。因此，MSS直肠癌的器官保存作为根治性手术的替代方案逐渐成为可行的选择。对于新辅助治疗后达到cCR或接近cCR的患者，可以安全地实施器官保存，且发病率较低。患者选择可以在新辅助治疗之前进行以获得更高的概率，也可以在仔细评估之后进行以获得有利的结果。那些获得良好临床反应的患者可通过非手术治疗、器官保存手术或单独放射治疗进行治疗，然后进行严格监测。与根治性手术相比，经过仔细选择和保留器官的患者的肿瘤学结果似乎并不差，术后发病率也较低。然而，应该进行更多的研究，以寻求更好的肿瘤消退，并最大限度地提高 MSS 直肠癌器官保存的可能性。