Locoregional Approaches to Colorectal Liver Metastasis – Radiation Options

While the standard of care for patients with limited colorectal liver metastases remains surgical resection, liver directed therapies such as radiofrequency ablation, radioembolization, and external beam radiation therapy have emerged to treat those who are not surgical candidates. Historically, these approaches were considered palliative; however, with advancements in systemic therapy, image-guided technologies, and motion management, ablative doses of radiation are now possible to liver metastases in a focal manner and can result in durable control with limited toxicity. In this chapter, we review how a multidisciplinary approach that includes application of novel radiation technologies including stereotactic body (SBRT) and proton beam therapy, and hypofractionated radiation regimens can result in improved survival outcomes and quality of life for patients with CRC liver metastases. Future directions include combinations of MR guided adaptive planning with ablative SBRT in conjunction with targeted and immune therapies, which carry exciting promise for further improvement of survival and locoregional control metrics.