Cetuximab Maintenance Treatment Versus Continuation After Induction Therapy in mCRC

This study is try to evaluate the effect of cetuximab monotherapy as maintenance treatment, versus continuation after 8 courses of induction therapy with cetuximab plus standard chemotherapy regimen (FOLFIRI or mFOLFOX6）in metastatic colorectal cancer (mCRC) patients. The maintenance treatments are continued until disease progression or untolerated toxicity. The aim of this study is to demonstrate that cetuximab monotherapy is non-inferior to continuation treatment, in those mCRC patients who responded to induction therapy(SD, PR, or CR), and carry biomarker-panels (KRAS, NRAS, BRAF, and PIK3CA) favor EGFR antibody. Furthermore, the mutation status of biomarker panel consist of KRAS, NRAS, HRAS, BRAF, EGFR, ERBB2, ERBB3, PIK3CA, PTEN, SMAD4, SMAD2, TGFBR2, cMET, Src, mTOR, VEGFR1, VEGFR2, EPHA2, MSI, TP53, ERCC1, ERCC5, KCNQ5, ILK, and Myc will be analyzed by NGS sequencing. The ctDNA as surrogate marker via liquid biopsy will be conducted before randomization, during maintenance treatment, and disease progression.