Recurrent Central Nervous System (CNS) lesions:
Primary CNS tumor recurrences after radiotherapy (38,39) and recurrent brain metastases (40) have been safely retreated with radiosurgery (38,40) or stereotactic radiotherapy (39).

Recurrent primary CNS tumors have been radiosurgically treated with survival extension of 7-8 months and no significant complications (38,39). Occasional long-term survivals in patients with small volume recurrences have been reported (38,39).

The retreatment result has been more durable with radiosurgery for recurrent brain metastases (metastases means tumors that have spread to the brain from primary malignant tumors elsewhere in the body), with an 84% rate of local control 2 years following radiosurgical retreatment (40). In the case of brain metastatic lesions, the 84% 2 year local control rate and 57% overall brain disease-free rate appears to significantly exceed the result reported with standard radiotherapy retreatment (11).