Anaplastic thyroid carcinoma: current diagnosis and treatment.

BACKGROUND Anaplastic thyroid carcinoma (ATC), accounting for 5% to 15% of primary malignant thyroid neoplasms, is one of the most aggressive solid tumors in humans. Generally, it is rapidly fatal, with a mean survival of six months after diagnosis. Multimodality treatment with surgery and/or external beam radiotherapy and chemotherapy are of fundamental importance for local control of disease and to enhance survival. DESIGN We evaluated consecutive patients with ATC observed at the Mayo Clinic from 1971 to 1993 and reviewed relevant articles published in major English-language medical journals. We used the MEDLINE database, selected bibliographies, and articles available in our personal files. RESULTS ATC usually does not concentrate radioiodine or express thyroglobulin. It is essential to verify the diagnosis histologically because insular thyroid cancer, lymphomas, and medullary thyroid cancer are occasionally confused with undifferentiated neoplasms. Immunohistochemical study is helpful in establishing the diagnosis. Multimodal therapy and the development of effective systemic chemotherapeutic agents should result in improvements in survival, although no single agent has yet been identified. CONCLUSIONS Aggressive multimodality treatment regimens show promise in improving local control in patients with ATC. However, survival rates remain low. Despite intense application of such therapy, no standardized successful treatment protocol has been established.