First-line Treatment of MCapOX + Cetuximab Vs. MFOLFOX6 + Cetuximab for RAS/BRAF Wild-type, MSS, Unresectable Left-Sided MCRC: a Multicenter, Randomized, Controlled, Phase III Study

Inclusion Criteria: * Able to provide written informed consent and can understand and comply with the requirements of the study. * Men and women ≥ 18 years of age. * Patients with histologically or cytologically confirmed RAS and BRAF wild-type, MSS/pMMR, metastatic left-sided colorectal adenocarcinoma. * Presence of at least one evaluable lesion, as defined in RECIST Version 1.1. * With an Eastern Cooperative Oncology Group (ECOG) performance status of 0-1. * No palliative first-line chemotherapy, targeted, immunotherapy, or prior platinum-based adjuvant chemotherapy, relapse more than 12 months from the end of adjuvant chemotherapy. * According to the imaging findings and surgical assessment of initial unresectable, synchronous metastatic colorectal cancer, no serious complications of the primary tumor (obstruction, perforation, massive hemorrhage that cannot be treated in internal medicine, etc.) . * Requirements for lab indicators: neutrophils ≥ 1.5 × 10\^9/L, platelets ≥ 75 × 10\^9/L, hemoglobin ≥ 8 g/dL; total bilirubin ≤ 1.5 × upper limit of normal (UNL); ASAT (SGOT) and/or ALAT (SGPT) ≤ 2.5 × UNL (≤ 5 × UNL if liver metastases); alkaline phosphatase ≤ 2.5 × UNL (≤ 5 × UNL if liver metastases, ≤ 10 × UNL if bone metastases); LDH \< 1500 U/L; creatinine clearance (calculated according to Cockcroft and Gault formula) \> 50 mL/min or serum creatinine ≤ 1.5 × UNL. Exclusion Criteria: * Patients with mCRC who were initially resectable with R0 resection or r…