[Expert consensus on neoadjuvant therapy with short-course radiotherapy followed by chemotherapy combined with immunotherapy for patients with mismatch repair-proficient/microsatellite stable locally advanced rectal cancer (2025 edition)].

Rectal cancer is one of the most common malignant tumors in China, with more than half of patients diagnosed at the locally advanced stage. Currently, the standard treatment for locally advanced rectal cancer (LARC) primarily involves neoadjuvant chemoradiotherapy followed by radical surgery. The advent of immune checkpoint inhibitors has revolutionized the neoadjuvant treatment landscape for mismatch repair-deficient/microsatellite instability-high (dMMR/MSI-H) rectal cancer. However, most rectal cancer patients exhibit mismatch repair-proficient/microsatellite stable (pMMR/MSS) status and show poor responsiveness to immunotherapy. In recent years, multiple studies have demonstrated that neoadjuvant short-course radiotherapy followed by chemotherapy and immunotherapy can improve the pathological complete response rate in pMMR/MSS LARC patients. Nevertheless, controversies persist regarding patient selection, efficacy evaluation, adverse event management, postoperative adjuvant therapy, and follow-up strategies. Considering the Colorectal Surgery Group of the Surgery Branch of the Chinese Medical Association, in collaboration with the Colorectal and Anal Surgery Committee of the Chinese Research Hospital Association, the Chinese Colorectal Cancer Clinical Research Collaborative Group, and related experts, has developed this consensus document by referencing domestic and international research advancements. The aim is to provide standardized guidance for the clinical application of this treatment approach.