Tislelizumab Combined With Chemotherapy (CAPOX) in the Perioperative Treatment of MSI-H/dMMR Stage II or III Colorectal Cancer

Inclusion Criteria: 1. ECOG: 0\~1; 2. Patients with colon or rectal adenocarcinoma confirmed by histology or cytology; 3. The tissue specimens are confirmed as MSI-H by PCR or NGS. If the patients are dMMR by immunohistochemistry, they need to be confirmed as MSI-H by PCR (2021 Expert Consensus on Immunotherapy for Patients with Colorectal Cancer); 4. Patients with clinical stage II or III (cT3-T4 N0 M0 or Tany N+M0, clinically positive lymph nodes are defined as any lymph node ≥ 1.0 cm); 5. Expected survival period ≥ 12 weeks; 6. The subjects voluntarily joined the study, signed the informed consent form, had good compliance, and cooperated with follow-up visits. Exclusion Criteria: 1. Have received anti-tumor therapy; 2. Have received PD-(L)1 or CTLA-4 treatment; 3. The patient has any active autoimmune disease or has a history of autoimmune disease (such as the following, but not limited to: autoimmune hepatitis, interstitial pneumonia, uveitis, enteritis, hepatitis, hypophysitis, vasculitis, nephritis , hyperthyroidism; patients with vitiligo; asthma that has been completely remitted in childhood and does not require any intervention in adulthood can be included; patients with asthma requiring medical intervention with bronchodilators cannot be included); 4. Patients are using immunosuppressants or systemic hormone therapy to achieve the purpose of immunosuppression (dose\>10mg/day prednisone or other equivalent hormones), and continue to use within 2 weeks before enrollment; 5. Patients with any severe and/or uncontrolled diseases 6. Urine routine prompts urine protein ≥ ++, and confirmed 24-hour urine protein quantity \> 1.0g; 7. Pregnant or lactating women; 8. Patients with other malignant tumors within 5 years (except cured basal cell carcinoma of the skin and carcinoma in situ of the cervix); 9. Those who have a history of psychotropic drug abuse and cannot quit or patients with mental disorders;