This study aims to explore the following key questions: 1) whether replacing ordinary irinotecan in VIC protocol with irinotecan liposomes can improve the safety and efficacy of BRAF V600E mutation in second-line treatment of metastatic colorectal cancer; 2) To provide a reference for identifying the dominant population for the benefit of irinotecan liposomes through the exploration of a range of biomarkers (including but not limited to ctDNA, immune microenvironmental indicators, tumor mutation load, lymphocyte subsets, cytokines, gut microbes, and others). Thus, it provides more treatment options for BRAF V600E mutations in patients with metastatic colorectal cancer
