CLINICAL STUDY - PATIENT STUDY Gamma knife radiosurgery for metastatic brain tumors from thyroid cancer In-Young Kim Æ Douglas Kondziolka Æ Ajay Niranjan Æ John C. Flickinger Æ L. Dade Lunsford Received: 22 November 2008 / Accepted: 30 December 2008 / Published online: 13 January 2009 Ó Springer Science+Business Media, LLC. 2009 Abstract 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 metasta- ses 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 pro- cedure-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. Keywords Cerebral metastasis Á Gamma knife radiosurgery Á Medullary thyroid cancer Á Papillary thyroid cancer Á Radiation therapy Á Stereotactic radiosurgery Á Thyroid cancer Abbreviations GKR Gamma knife radiosurgery MRI Magnetic resonance imaging SPGR Spoiled-Gradient Recalled Acquisition in Steady State SRS Stereotactic radiosurgery WBRT Whole brain radiation therapy Introduction Stereotactic radiosurgery (SRS) for cerebral metastases is associated with high local control rates [1–11]. Even cerebral metastases considered resistant to whole brain radiation therapy can be successfully treated with SRS [2, 12, 13]. The response rate may differ depending on the tumor histology [9, 14]. Although thyroid cancer is a rel- atively common malignancy that may metastasize within the body, brain metastases from thyroid cancer are extre- mely rare [15]. The reported incidence is approximately 1% of all cases of thyroid carcinoma [15–18]. There are only rare reports on the management of cerebral metastases from thyroid cancer [15, 17, 19]. The role of SRS has not been defined for this pathology and only scattered cases have been reported [20–22]. We retrospectively studied the outcomes of gamma knife radiosurgery (GKR) for patients with cerebral I.-Y. Kim Á D. Kondziolka Á A. Niranjan Á L. D. Lunsford Department of Neurological Surgery, Center for Image-Guided Neurosurgery, University of Pittsburgh, Pittsburgh, PA, USA J. C. Flickinger Department of Radiation Oncology, Center for Image-Guided Neurosurgery, University of Pittsburgh, Pittsburgh, PA, USA I.-Y. Kim Brain Tumor Clinic & Gamma Knife Center, Department of Neurosurgery, Chonnam National University Hwasun Hospital & Medical School, Chonnam, South Korea D. Kondziolka (&) University of Pittsburgh Medical Center–Presbyterian, Suite B-400, 200 Lothrop Street, Pittsburgh 15213, PA, USA e-mail: kondds@upmc.edu 123 J Neurooncol (2009) 93:355–359 DOI 10.1007/s11060-008-9783-2