Trends in radiation therapy for the treatment of metastatic and oligometastatic disease in 2010

The role of radiation therapy in metastatic disease has evolved from palliative to potentially curative intent for selected oligometastases using highly conformal radiation techniques, including extracranial stereotactic body radiotherapy (SBRT) in the last decade. SBRT has a potential to use small numbers of large doses aiming at achieving high rates of local control while preserving the quality of life even in highly pretreated patients. A wide range of techniques, doses, and dose fractionation schedules can be found. However, the 2-year local control is around 80% for lung metastases with corresponding 2-year survival of 50%, and a 5% rate of grade III or higher radiation toxicities. The 2-year local control varies between 57 and 92% for liver metastases and radiation-induced liver disease is exceptional provided that 700 cm3 of healthy liver are irradiated to less than 15 Gy in three fractions or more. Stereotactic radiation is also particularly interesting for spinal, and cranial metastases and reirradiations. Also, it has come into focus that associations of chemotherapy or targeted therapies and radiation may be used for optimized treatment of limited metastatic disease and that irradiation of the primary tumor may be recommended in the context of metastatic disease. It also appears that the definition of target volumes for palliative radiation therapy and scores to assess for life expectancy-based need for irradiation should be improved.