Neoadjuvant Radiochemotherapy Combined With QL1706 for Low Rectal Cancer

Inclusion Criteria: 1. Patients willing to receive neoadjuvant therapy. 2. Aged 18-75 years, regardless of gender. 3. Diagnosed with low-lying rectal adenocarcinoma (tumor located ≤7 cm from the anal verge) via colonoscopy, endorectal ultrasound, and pelvic high-resolution MRI, without distant metastasis. 4. Histopathologically confirmed rectal adenocarcinoma. 5. Good patient compliance, able to attend follow-up visits as required. 6. ECOG performance status score of 0-1. 7. Laboratory tests meeting the following criteria: i. WBC ≥3.5×10\^9/L, ANC ≥1.8×10\^9/L, platelets ≥100×10\^9/L, hemoglobin ≥100 g/L. ii. INR ≤1.5, APTT ≤1.5×ULN, or PTT ≤1.5×ULN. iii. Total bilirubin ≤1.25×ULN; ALT/AST ≤5×ULN. iv. 24-hour creatinine clearance ≥50 mL/min or serum creatinine ≤1.5×ULN. 8. Voluntary signed informed consent. Exclusion Criteria: 1. History of malignant colorectal tumors. 2. Patients requiring emergency surgery (e.g., intestinal obstruction, perforation, or hemorrhage). 3. Known allergy to capecitabine, oxaliplatin, PD-L1 inhibitors, CTLA-4 inhibitors, or related drugs. 4. Histopathology indicating poorly differentiated adenocarcinoma or signet ring cell carcinoma. 5. Unstable systemic diseases, including but not limited to: Severe infection, uncontrolled diabetes, refractory hypertension, unstable angina, cerebrovascular accident, myocardial infarction, congestive heart failure, life-threatening arrhythmias, or severe hepatic/renal/metabolic disorders. 6. Conditions (e.g., psychiatric disorders, substance abuse) that may increase treatment risk, compromise compliance, or confound study results. 7. Participation in another interventional clinical trial or use of investigational drugs within 30 days prior to screening. 8. Pregnancy, lactation, or refusal to use effective contraception during the study. 9. Other conditions deemed unsuitable by the investigator.