New combo therapy aims to improve survival in hard-to-treat rectal cancer

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Age 18-75 years, regardless of gender; 2. Stage II/III disease (cT3-T4N0 or cT2-4N+) without distant metastasis on magnetic resonance imaging (MRI) or endoscopic ultrasound (EUS), according to the 8th edition of the AJCC Cancer Staging Manual (2018); 3. The lower boundary of the lesion is ≤ 10 cm from the anal verge, confirmed by colonoscopy or digital rectal examination; 4. Pathologically confirmed or re-reviewed rectal adenocarcinoma; 5. Eastern Cooperative Oncology Group (ECOG) performance status of 0-1; 6. Meet the following laboratory diagnostic indicators: Hemoglobin ≥ 90 g/L, white blood cell count ≥ 3.5×10⁹/L; 7. Neutrophil count ≥ 1.5×10⁹/L, platelet count ≥ 100×10⁹/L; 8. Creatinine ≤ 1.0×upper normal limit (UNL), blood urea nitrogen (BUN) ≤ 1.0×UNL; 9. Alanine aminotransferase (ALT) ≤ 1.5×UNL; 10. Aspartate aminotransferase (AST) ≤ 1.5×UNL; 11. Alkaline phosphatase (ALP) ≤ 1.5×UNL; 12. Total bilirubin (TBIL) ≤ 1.5×UNL; 13. Urinary protein (-); normal bleeding and coagulation time. 14. No history of allergy to platinum-based drugs; 15. For patients with primary rectal cancer, no surgery (except palliative colostomy), chemotherapy, or other anti-tumor treatments have been performed from diagnosis to enrollment; 16. No previous radiation therapy to the intended radiation field; 17. Signed informed consent form. Exclusion Criteria: 1. Previous treatment with anti-PD-1/L1, anti-CTLA-4 immunotherapeutic drugs, or other experimental immunotherapeutic agents; 2. Patients with severe autoimmune diseases: active inflammatory bowel disease (including Crohn's disease, ulcerative colitis), rheumatoid arthritis, scleroderma, systemic lupus erythematosus, autoimmune vasculitis (such as Wegener's granulomatosis), etc.; 3. Symptomatic interstitial lung disease or active infectious/non-infectious pneumonia; 4. Patients with risk factors for intestinal perforation: active diverticulitis, intra-abdominal abscess, gastrointestinal (GI) obstruction, abdominal cancer, or other known risk factors for intestinal perforation; 5. History of other malignant tumors, excluding curable non-melanoma skin cancer and carcinoma in situ of the cervix; 6. Patients with active infection, heart failure, myocardial infarction within 6 months, unstable angina pectoris, or unstable arrhythmia; 7. Physical examination or clinical laboratory findings that the investigator believes may interfere with the results or increase the risk of treatment complications in patients, or other uncontrollable diseases; 8. Lactating or pregnant women; 9. Congenital or acquired immunodeficiency diseases including human immunodeficiency virus (HIV), or history of organ transplantation or allogeneic stem cell transplantation; 10. Known active hepatitis B virus (HBV) infection (HBV-DNA ≥ 2000 U/mL), hepatitis C virus (HCV) infection, or active pulmonary tuberculosis infection; 11. Patients who have received tumor vaccines or other vaccines within 4 weeks before the start of treatment; (Note: Seasonal influenza vaccines for injection are mostly inactivated vaccines and thus allowed, while intranasal preparations are usually live attenuated vaccines and thus not allowed); 12. Patients receiving concurrent use of other immunomodulators, chemotherapeutic drugs, drugs in other clinical studies, or long-term cortisol therapy are not eligible for enrollment; 13. Patients with mental illness, substance abuse, or social problems that affect compliance will not be enrolled after review by doctors; 14. Patients with allergies or contraindications to the study drugs.