Management of brain metastases from thyroid carcinoma: a study of 16 pathologically confirmed cases over 25 years

Brain metastasis is an uncommon, morbid complication of metastatic thyroid carcinoma. Because of its rarity, management often is problematic. To help contribute to the management of this disease entity, the authors present herein what to their knowledge is the largest series reported to date in which all patients had biopsy proven confirmation of their brain metastases.

The authors report a series of 16 patients with metastatic thyroid carcinoma to the brain who were treated between 1976-2000. The Mayo Clinic database was used to locate and review charts and radiology and pathology reports, and all biopsy specimens were reviewed by one pathologist. The histologic types of carcinoma included 10 papillary carcinomas, 2 follicular carcinomas, 1 Hürthle cell carcinoma, 1 medullary carcinoma, 1 insular carcinoma, and 1 anaplastic carcinoma. Given the small sample size, statistical analyses were not performed.

Surgical resection of brain metastases was associated with a trend toward longer survival (20.8 months vs. 2.7 months for no surgical intervention in selected patients) Whole brain external beam radiation therapy produced disease regression in three of the four evaluable patients. Gamma knife radiosurgery and radioactive iodine therapy appear to play limited, but beneficial, therapeutic roles. Overall, survival after the diagnosis of brain metastasis is reported to be longer than that noted with other solid tumors (17.4 months), and the majority of patients die of their extracranial disease (85% in the current series).

The results of the current study indicate that local therapies appear to control brain metastases in the large majority of thyroid carcinoma patients with metastases to the brain.