A Pospective, Single-arm, Multicenter Clinical Trial Evaluating Preoperative Neoadjuvant mFOLFOX6 Chemotherapy in Combination With PD1 Monoclonal Antibody in MSS/pMMR Locally Advanced Rectal Cancer

Exclusion Criteria

• •1. Patients with distant metastasis
• •2. History of receiving chemotherapy, radiotherapy, targeted therapy, or immunotherapy.
• •3. Active autoimmune disease requiring systemic treatment within the 2 years prior to enrollment.
• •4. History of other malignancies within the past 5 years, excluding cured cervical carcinoma in situ or basal cell carcinoma of the skin.
• •5. History of HIV infection, or active chronic hepatitis B or C with high viral DNA copy numbers.
• •6. Patients with active tuberculosis currently receiving anti-tuberculosis treatment or treated with anti-tuberculosis therapy within the past year prior to screening.
• •7. Known or suspected allergy to the study drug or any study-related medications administered.
• •8. Presence of severe cardiovascular or cerebrovascular disease.
• •9. Within 14 days prior to the first dose, presence of a severe active or uncontrolled infection requiring systemic therapy, or unexplained fever \>38.5°C.
• •10. Receiving systemic corticosteroid treatment or other immunosuppressive agents within 14 days prior to the first dose, or immunostimulants within 4 weeks.
• •11. History of confirmed neurological or psychiatric disorders, including epilepsy or dementia.
• •12. The participant may be unable to complete the study due to other reasons, or the investigator considers them unsuitable for inclusion.
• •13. Refusal to sign the informed consent form.