Gamma Knife Radiosurgery in Thyroid Cancer Patients with Brain Metastasis : Treatment Results |
Moinay Kim, Do Hoon Kwon, Jeong Hoon Kim, Wonhyoung Park, Do Hee Lee, Chang Jin Kim |
Department of Neurological Surgery, Asan Medical Center, College of Medicine, University of Ulsan College of Medicine, Seoul, Korea |
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Abstract |
Objective To evaluate the efficacy of gamma knife radiosurgery (GKRS) in treatment of brain metastases from thyroid cancer.
Methods Between June 1995 and September 2012, 20 patients underwent treatment at our hospital for 51 brain metastases from a thyroid cancer. The median age was 55.8 years (range : 42-69 years) and there were 7 male (35%) and 13 female (65%) patients. The average number of metastases was 2.46 (range : 1-10) and single metastases were most common (12 patients). The mean number of GKRS was 1.57 (range : 1-4). A mean dose of 22.31Gy (range : 10-33) was prescribed at the tumor border. The mean tumor volume was 5.75cc (range : 0.3-16.50cc).
Results Of the 20 patients evaluated, 16 patients (80.0%) showed tumor control and 4 patients (20.0%) showed tumor progression. In the patients with tumor progression, 1 patient (5.0%) required whole brain radiation therapy (WBRT), 2 patients (10.0%) needed a second GKRS. The remaining 1 patient (5.0%) underwent surgery after showing new neurologic deficits. The overall median survival after GKRS was 34.7 months (range : 1-168 months) ; 27.1 months for patients in recursive partitioning analysis (RPA) class 1, 26.5 months for patients in RPA class 2, and 4.5 months for patients in RPA class 3. The median progression- free survival after treatment was 18.6 months. The median diagnosis period of cerebral metastases after thyroid cancer treatment was 7.8 years (range : 8 months-20 years). The histopathological subtypes of thyroid cancers can result in a different outcome. As papillary (14 patients, 70%), follicular (5 patients, 25%) and 1 medullary (5%) case showed significance in univariate analysis (KPS score, p=0.048).
Conclusions GKRS is an efficient tool for treating thyroid cancer patients with brain metastases as it helps to reduce tumor volume thereby increase tumor control rates and median survival. These results support the usefulness of GKRS in thyroid cancer patients. |
Key Words:
Brain metastases, Gamma knife radiosurgery, Thyroid cancer. |
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