Brain Metastases from Thyroid Carcinoma: Prognostic Factors and Outcome

Abstract

Intracranial metastases from thyroid cancer are rare. Although the prognosis of thyroid cancer patients is generally favorable, the prognosis of patients with intracranial metastases from thyroid cancer has been considered unfavorable having a lower survival rate than those without intracranial involvement. Many questions about their management remain unclear. The aim of this study was to analyze the characteristics, treatments, and outcomes of patients with brain metastases from thyroid cancer. Among 4320 patients with thyroid cancer recorded in our institutional database over a 30-year period, 20 patients with brain metastasis were retrospectively collected and analyzed. The clinical characteristics, histological type of primary cancer and metastatic brain tumor, additional previous distant metastasis, treatment modalities, locations and characteristics on radiologic findings, time interval between the first diagnosis of the primary thyroid cancer and brain metastasis, and survival were analyzed. The mean age at initial diagnosis was 59.3 ± 14.1 years, and at the manifestation of diagnosis of cerebral metastasis 64.8 ± 14.9 years. The histological types of the primary thyroid cancers were papillary in ten patients, follicular in seven, and poorly differentiated carcinoma in three. The average interval between the diagnosis of thyroid cancer and brain metastasis was 63.4 ± 58.4 months (range, 0-180 months). Ten patients had a single intracranial lesion and 10 patients had multiple lesions. Surgical resection was primarily performed in 15 patients and whole-brain radiotherapy, radiotherapy or tyrosine kinase inhibitors were applied in the other 5 patients. Overall median survival time was 15 months after diagnosis of BM from TC (range: 1-252 months). Patients with thyroid cancer can develop brain metastasis even many years after diagnosis of the primary tumor. Our study demonstrates an increased overall survival of patients younger than 60 years of age at the time of diagnosis of brain metastasis. There was no difference in survival between patients with brain metastasis from papillary or follicular thyroid carcinoma.