Brain Metastases from Thyroid Carcinoma: A Retrospective Study of 21 Patients

Abstract

Brain metastases (BM) from differentiated thyroid carcinoma (DTC) are uncommon, and many questions about their management remain unsolved. The objective of this retrospective study was to analyze the characteristics, treatments, and outcomes of patients with BM from DTC. Among the 1523 patients with a DTC prospectively recorded in institutional databases between 1989 and 2012, 21 patients (1.4%) with BM were retrospectively retrieved. Patient characteristics, histological findings on initial thyroidectomy specimen, treatments, and time to death were reviewed. Overall survival (OS) was calculated using the Kaplan-Meier method. Survival curves for various subgroups of patients according to baseline characteristics and treatment received were compared. The mean age at initial and BM diagnosis was, respectively, 52.7 and 63.2 years. World Health Organization performance status (PS) at BM diagnosis was good (<2) for 12 patients and poor (≥2) for 9. The initial carcinoma was papillary for 12 patients, follicular for 5, and poorly differentiated for 4. Eighteen patients had other previous and/or synchronous distant metastases: lung (11), bone (10), and others (2 peritoneum, 1 liver, 1 adrenal gland, and 1 uterine cervix). The average interval between the first metastasis and the BM was 3 years (range 0-35.6 years). The mean number and the mean size of BM were, respectively, 2.8 (range 1-10) and 22.5 mm (range 3-44 mm). Surgery was performed for 10 patients and radiotherapy (RT) for 18, with 2 stereotactic radiosurgery (SRS), 2 conformal RT limited to the metastasis, and 15 whole-brain RT. The median OS after BM was 7.1 months. OS at 1 and 2 years were 41.6% and 35.6%. PS and realization of surgery or SRS had an impact on survival, with OS of 27 months when PS <2 versus 3 months when PS ≥2 (p=0.0009), and OS of 11.9 months after surgery or SRS versus 3.6 months in their absence (p=0.04). BM from thyroid cancer may have an indolent evolution with survival of one to two years or longer for specific groups of patients. Therefore, aggressive treatment options such as neurosurgery and RT should be strongly considered in patients with good PS.