Background: Anaplastic thyroid carcinoma (ATC), accounting for 5% to 15% of
primary malignant thyroid neoplasms, is one of the most aggressive solid t
umors in humans. Generally, it is rapidly fatal, with a mean survival of si
x months after diagnosis. Multimodality treatment with surgery and/or exter
nal beam radiotherapy and chemotherapy are of fundamental importance for lo
cal control of disease and to enhance survival.
Design: We evaluated consecutive patients with ATC observed at the Mayo Cli
nic from 1971 to 1993 and reviewed relevant articles published in major Eng
lish-language medical journals. We used the MEDLINE database, selected bibl
iographies, and articles available in our personal files.
Results: ATC usually does not concentrate radioiodine or express thyroglobu
lin. It is essential to verify the diagnosis histologically because insular
thyroid cancer, lymphomas, and medullary thyroid cancer are occasionally c
onfused with undifferentiated neoplasms. Immunohistochemical study is helpf
ul in establishing the diagnosis. Multimodal therapy and the development of
effective systemic chemotherapeutic agents should result in improvements i
n survival, although no single agent has yet been identified.
Conclusions: Aggressive multimodality treatment regimens show promise in im
proving local control in patients with ATC. However, survival rates remain
low. Despite intense application of such therapy, no standardized successfu
l treatment protocol has been established.