Multi-Session Radiosurgery for Numerous Small Brain Metastases

Objectives: Treatment of multiple brain metastases more than 10 is challenging. Whole brain radiotherapy ( WBRT) is generally believed to be the first treatment choice. In order to escape from mental deterioration after WBRT, we have performed Gamma Knife stereotactic radiosurgery (GKS) for numerous small brain metastases. Methods: Twelve cases of numerous (more than 30) brain metastases were treated by GKS. Mean total session number was 5.42 times, ranging 2 to 17. Each tumor was treated with the margin dose between 14 to 20 Gy. The tumor number treated in whole sessions was ranged from 31 to 144 (mean, 70.8). Results: Almost all the irradiated tumors either disappeared or shrank at the patient's death or at the last follow-up, though new metastatic tumors were subsequently developed in some cases which required an additional treatment with GKS. At the last follow-up (3 to 51 months after GKS), nine cases were alive and well and three were dead. As adverse effects, two cases demonstrated seizures by radiation brain injury and another showed a gait disturbance. No apparent mental deterioration was observed during follow-up. Conclusion: Radiosurgery for numerous small brain metastases may be preferable rather than WBRT.