Outcome of repeated radiosurgery for recurrent metastatic brain tumors

Objective: We investigated the outcome of repeated gamma knife radiosurgery (GKS) for local or remote recurrence after initial radiosurgery. Material and methods: We retrospectively reviewed 204 patients who were treated with GKS. Among them 43 patients (21%) underwent GKS more than once. The second GKS was given for recurrence at the previously treated sites in 16 patients, new lesions at remote sites in 13, and both local recurrence and new lesions in 14. Results: The median survival from the first GKS was 36 (7-190) weeks in all patients and 68 (16-156) weeks in 43 patients with repeated GKS. The median time from the first GKS to the second was 37 weeks. The median survival from the second radiosurgical intervention was 32 (7-132) weeks. Local control rate at 6 months after salvage GKS was 90.7%. RPA class was the commonly dominant prognostic factor in both initial and salvage GKS. Conclusion: Recurrence is common for patients with metastatic brain tumors after initial radiosurgery. Local control and survival time after salvage treatment are comparable with those after initial radiosurgery. GKS as a salvage treatment may provide additional survival benefit in selected patients.