Abstract:
Colorectal cancer (CRC) is a common malignant tumor. The treatment of patients with advanced disease still faces severe challenges. Among patients with metastatic colorectal cancer (mCRC), most of those with microsatellite stable (MSS)/proficient mismatch repair (pMMR) tumors are highly insensitive to monotherapy with immune checkpoint inhibitors. With in-depth investigations into the mechanisms of the tumor immune microenvironment in MSS/pMMR CRC, the combination strategies of immunotherapy and targeted therapy have become a key direction to break through the treatment bottleneck in this population. These strategies include combinations of immunotherapy with antiangiogenic agents, epidermal growth factor receptor inhibitors, histone deacetylase inhibitors, and MAPK pathway inhibitors. Although the current relevant evidence is mainly derived from early-phase clinical trials, a number of studies demonstrated that immunotherapy combined with targeted therapy can improve the objective response rate and survival benefit in patients with MSS/pMMR mCRC and shows remarkable efficacy advantages in specific subgroups. This article systematically reviews the biological basis and clinical research progress of relevant combination therapeutic strategies, discusses potential beneficiary subgroups, and prospects future research directions. It aims to provide theoretical evidence and clinical references for optimizing the individualized treatment paradigm for this large patient population.