Gamma knife radiosurgery for metastatic brain tumors from thyroid cancer

Objective We report our experience using gamma knife radiosurgery (GKR) for brain metastasis from thyroid cancer, which is extremely rare. Methods Between 1995 and 2007, 9 patients with 26 metastatic brain tumor(s) from thyroid cancer underwent GKR. The mean patient age was 58 years (range: 10-78). Seven patients had metastases from papillary thyroid cancer, and two from medullary thyroid cancer. Five patients had solitary tumors, and four patients had multiple metastases. Three patients who had multiple metastases also underwent whole brain radiation therapy (WBRT). The mean tumor volume was 2.4 cc (range: 0.03-14.0). A median margin dose of 18.0 Gy (range: 12-20) was delivered to the tumor margin. Results Tumor control was obtained in 25 out of 26 tumors (96%). The median progression-free period after GKR was 12 months (range: 4-53). The overall median survival after GKR was 33 months (range: 5-54). There were no procedure-related complications and six patients are still living 5-54 months after GKR. Conclusions Radiosurgery is an effective and minimally invasive strategy for management of brain metastases form thyroid cancer.