How soon will the patient with metastasis return for radiosurgery?

Object: Stereotactic radiosurgery for brain metastasis has become one of the standard treatment options in recent years. Some patients must undergo repeated stereotactic radiosurgery for new lesions. The authors retrospectively reviewed their data to estimate how soon the patients undergo repeated radiosurgery for new lesions.
Methods: Between October 1999 and March 2006, 1081 patients with brain metastases underwent Gamma Knife surgery (GKS) at Tokyo Women's Medical University. One hundred and forty-nine patients in whom GKS had been performed two or more times were evaluated. There were 68 men and 81 women with a median age of 61 years (range 29-90 years). The authors analyzed data on patient age, number of treated lesions, and period between GKSs. Follow-up imaging was performed in almost all patients every 2 to 3 months after GKS. The number of lesions treated in a single session varied from one to 35. The median interval between GKSs was 26 weeks (range 3-175 weeks) for patients with breast cancer and 23 weeks (range 4-179 weeks) for patients with non-small cell lung carcinoma.
Conclusions: It would appear that follow-up imaging studies should be obtained every 2 to 3 months after GKS to monitor patients for tumor recurrence.