Anaplastic thyroid carcinoma. Association with differentiated thyroid cancer.

Fourteen cases of anaplastic thyroid carcinoma (ATC) treated at Baylor College of Medicine, Houston, during a 19-year period were reviewed. There was a 1.3:1 female preponderance, and the median patient age was 62 years. Ten (71%) of the anaplastic tumors either followed or occurred simultaneously with a well-differentiated thyroid carcinoma. This finding adds support to the theory that ATC usually results from the transformation of well-differentiated thyroid carcinoma. A combination of surgery, radiation therapy, and chemotherapy was utilized for most patients. In this series of patients, the median duration of survival was four months following diagnosis, with only three patients (21%) alive at one year. Despite aggressive therapy, the prognosis for ATC remains poor.