Repeat Stereotactic Radiosurgery for Brain Metastasis

Recurrent brain metastasis, following initial treatment which may include whole-brain radiation therapy (WBRT), surgery, stereotactic radiosurgery (SRS), or a combination of these treatment options, is more prevalent due to better survival from improved cancer therapeutics and more frequent brain imaging to monitor recurrence. Relapse may be observed elsewhere in the brain, but also local despite upfront treatment. Effective salvage options, such as SRS, are necessary to treat recurrences to avoid neurologic death. Fractionated SRS can be considered for potential lower toxicity risk. For larger tumors, staged SRS, which involves repeating SRS to the same area 1 month later, may help maximize local control, while keeping the risk of radiation necrosis low. This chapter discusses the use of SRS to treat local and distant relapse after WBRT, local recurrence after prior SRS, distant recurrence after prior courses of SRS, and upfront larger brain metastases in the form of staged SRS. The importance of confirming local recurrence following SRS prior to considering repeat SRS and the use of additional therapies such as Laser Interstitial Thermal Therapy (LITT) are also reviewed.