The goal of this clinical trial is to compare the efficacy and safety of the combination of immune checkpoint inhibitors (ICIs) and FOLFOX regimen compared to FOLFOX regimen alone in the neoadjuvant chemotherapy of locally advanced colorectal cancer. The main question aims to answer are:
Question 1: Compare the pathological complete response rate between the combination of ICIs and FOLFOX regimen and the FOLFOX alone.
Question 2: Compare the survival outcomes and safety between the combination of ICIs and FOLFOX regimen and the FOLFOX alone.
Two groups of participants will receive different new adjuvant chemotherapy regimens, and their efficacy will be compared.
Age 18 to 75, no gender restrictions;
Histologically or cytologically confirmed colorectal adenocarcinoma;
Clinically diagnosed as stage II/III colorectal cancer based on CT and/or MRI (according to the 8th edition of AJCC staging);
Sufficient tumor tissue specimens for mismatch repair protein expression or microsatellite instability testing;
Pathology is other malignant tumors besides adenocarcinoma, such as squamous cell carcinoma, gastrointestinal stromal tumor, melanoma, etc.;
Within 5 years prior to the first use of investigational drug, diagnosed with other malignant tumors, excluding effectively treated basal cell carcinoma, squamous cell carcinoma of the skin, and/or in situ cervical cancer and/or breast cancer effectively removed;
Any distant metastatic colorectal adenocarcinoma (according to AJCC 8th edition staging, determined as M1), including but not limited to distant lymph node metastasis, liver metastasis, lung metastasis, intraperitoneal dissemination, or malignant peritoneal effusion;
Various severe underlying diseases and autoimmune diseases (see protocol for details);