abstract
- Improvements with systemic therapy in controlling occult metastatic disease in patients with colorectal cancer and other solid malignancies have raised renewed interest in local therapies that can treat isolated or "oligo" sites of metastatic disease within the liver. Radiotherapy (RT) is a treatment option that can be offered to patients unsuitable for surgery or other ablative therapies. Technological advances in RT planning and delivery have made it possible to administer high doses conformally around focal liver metastases effectively. Methods to facilitate safe delivery of high-dose RT include conformal RT planning, stereotactic body RT, breathing motion management, and image-guided RT. The clinical experience in conformal RT and stereotactic body RT for liver metastases is emerging, with phase I and II trials demonstrating excellent local control and occasional long-term survivors. With appropriate patient selection and sparing of the uninvolved liver, serious toxicity can be avoided. Out-of-field recurrences are common, providing rationale for combining systemic or regional therapies with RT for these patients. Finally, randomized trials of RT for liver metastases are needed to better define the benefits of RT for these patients.