Radiation Therapy for Liver Metastases

Historically, metastatic disease to the liver has primarily been treated with systemic therapy alone. Early surgical series defined the role of local therapy to treat metastatic liver disease. Prior to the introduction of intensity-modulated radiation therapy (IMRT) and stereotactic body radiation therapy (SBRT), radiation oncologists were limited by the tolerance of the liver to radiation. In the past several decades, tremendous advancement in the field of radiation oncology has led to more conformal techniques, improved treatment planning software, and an overall ability to better deliver accurate treatment to the tumor. With the emergence of these improved techniques, more focal treatments with higher-dose radiation can be delivered to metastatic liver lesions while sparing normal liver parenchyma. Tumoricidal doses are now possible with conformal IMRT, image-guided radiation therapy (IGRT), and improved motion management, enabling clinicians to deliver ablative SBRT with local control rates exceeding 90% in modern series. The role of SBRT in liver metastases and the clinical data to support it will be discussed in this chapter.