Targeting Liver Metastases to Potentiate Immunotherapy in MS-Stable Colorectal Cancer—A Review of the Literature

SIMPLE SUMMARY: Immunotherapy is an innovative treatment that is highly effective against certain cancers, such as skin and lung cancer. However, for colorectal cancer, one of the most prevalent cancers, it does not benefit most patients. Recent research suggests that by treating liver metastases first, immunotherapy might become effective for those with colorectal cancer. This review delves into the current evidence supporting this strategy, aiming to understand its underlying mechanisms and determine the best way to implement it. If this approach gains widespread acceptance, it could revolutionize how we treat colorectal cancer patients. ABSTRACT: Immunotherapy has revolutionized the treatment of several cancers, including melanoma and lung cancer. However, for colorectal cancer, it is ineffective for 95% of patients with microsatellite-stable disease. Recent evidence suggests that the liver’s immune microenvironment plays a pivotal role in limiting the effectiveness of immunotherapy. There is also evidence to show that targeting liver metastases with locoregional therapies, such as surgery or irradiation, could potentiate immunotherapy for these patients. This review presents evidence from preclinical studies regarding the underlying mechanisms and from clinical studies that support this approach. Furthermore, we outline potential directions for future clinical trials. This innovative strategy could potentially establish immunotherapy as an effective treatment for MS-stable colorectal cancer patients, which are currently considered resistant.