A Multicenter, Open, Randomized, Phase II Trial：Short-course Radiotherapy or Long-course Chemoradiation Followed by MFOLFOXIRI Consolidation Chemotherapy for Organ Preservation in Low Rectal Cancer
Given the growing focus on preserving organ function and the utilization of neoadjuvant therapy, it is important to investigate and enhance the application of comprehensive neoadjuvant therapy in low rectal cancer. This approach aims to minimize or circumvent the organ dysfunction and subsequent decline in quality of life associated with radical surgery, with improving disease-free survival (DFS), while . Consequently, we propose to initiate a multicenter clinical trial to examine the medium- and long-term effectiveness of complete neoadjuvant therapy (comprising either short-course radiotherapy or long-course chemoradiation, followed by consolidation chemotherapy with mFOLFOXIRI) in increasing organ preservation rates in patients with low rectal cancer.
• Diagnosis: Histologically confirmed rectal adenocarcinoma. Preoperative Staging: Clinical stages cT2-4aN0-2. Tumor Location: Tumor's lower edge within 8cm from the anus, potentially affecting anal preservation or function.
• Metastasis Screening: Preoperative chest, abdomen, and pelvis CT to rule out distant metastasis.
• Biomarkers: Positive expression of pMMR (MSH1/MSH2/MSH6/PMS2) on tumor biopsy immunohistochemistry.
• Staging Methods: Combination of thoracic and abdominal pelvic CT, pelvic MRI, and endoscopic or transrectal ultrasound.
• Patient Characteristics Age: 18 to 70 years. Performance Status: ECOG score of 0-1. Life Expectancy: At least 2 years. Blood Counts: WBC \>4000/mm\^3, PLT \>100,000/mm\^3, Hb \>10g/dL (chronic anemia with Hb \< 10.0g/dL subject to multidisciplinary team review).
• Liver Function: Serum total bilirubin ≤1.5×ULN (≤3×ULN for Gilbert syndrome); AST and ALT ≤2.5×ULN.
• Renal Function: Serum creatinine ≤1.5×ULN or creatinine clearance \>50 mL/min. Other Criteria: Non-pregnant, not nursing, no other malignancies (except non-melanoma skin cancer or cervical carcinoma in situ) within the past 5 years, capable of providing informed consent, no severe comorbidities affecting survival.
• Prior Treatment No prior surgery, chemotherapy, or radiotherapy for rectal cancer. No prior biological therapy. No restrictions on previous endocrine therapy.