Clinical Research Directory

Inclusion Criteria 1. Age 18 years or older. 2. ECOG performance status of 0 or 1. 3. Histologically confirmed rectal adenocarcinoma. 4. Primary tumor located within 10 cm of the anal verge by pelvic MRI and/or rigid sigmoidoscopy. 5. Clinically involved regional lymph nodes (cN1-2) according to the AJCC 8th edition. 6. At least one additional high-risk feature: cT4 disease, cN2 disease, extramural vascular invasion, mesorectal fascia involvement, lateral pelvic lymph-node involvement, tumor deposits, or low rectal cancer (≤5 cm from the anal verge). 7. Baseline locoregional staging with contrast-enhanced pelvic MRI and chest/abdominal imaging excluding distant metastases. 8. Treatment-naïve with respect to systemic therapy and pelvic radiotherapy for the index rectal cancer and suitable for total mesorectal excision. 9. Adequate organ function and no medical contraindication to chemoradiotherapy. 10. Written informed consent before study-specific procedures. Exclusion Criteria 1. Prior pelvic radiotherapy. 2. Prior rectal surgery for the index cancer, including local excision or transanal procedures. 3. Radiologically or pathologically confirmed distant metastasis. 4. Locally recurrent rectal cancer. 5. Active inflammatory bowel disease. 6. History of another primary malignancy within the preceding 5 years, except adequately treated non-melanoma skin cancer or carcinoma in situ. 7. Pregnancy or lactation. 8. Severe or uncontrolled medical condition contraindicating chemoradiotherapy or surgery. 9. Clinically significant hypersensitivity to protocol systemic therapy that precludes treatment.