Radiation Therapy

Currently, the best curative treatment for colorectal liver metastasis is surgical resection. However, many patients are not viable surgical candidates. Stereotactic body radiotherapy (SBRT) is a well-established alternative treatment option for patients with liver metastases that are unsuitable candidates for surgical resection. Prior to the development of SBRT, conventional radiation therapy was studied for the treatment of liver metastases but demonstrated limited efficacy and significant toxicities due to the liver being a radio-sensitive organ. For example, conventional radiation of the whole liver posed a high risk of radiation-induced liver disease (RILD). SBRT differs from conventional radiation in that SBRT applies fewer fractions and higher doses of radiation focally and precisely to the tumor. This is possible due to advancements in technology with image guidance, motion management, and radiation delivery technologies. Numerous recent studies for colorectal liver metastases have shown evidence of encouraging local control and overall survival rates after treatment with SBRT, without increased rates of RILD. We review the technological advancements and clinical data supporting SBRT for colorectal liver metastases in this chapter.