Combination therapy for anaplastic giant cell thyroid carcinoma. Since 1981, 20 patients with anaplastic giant cell carcinoma of the thyroid have been prospectively treated according to a combination regimen of chemotherapy and external beam radiation therapy. Two types of chemotherapy were used every 4 weeks, depending on the patient's age. For those younger than 65 years, a combination of doxorubicin (60 mg/m2) and cisplatin (90 mg/m2) was given, and for older patients mitoxantrone (14 mg/m2) was used. Radiotherapy was carried out between Day 10 and Day 20 of the first four cycles of chemotherapy. It delivered 17.5 Gy in 7 fractions to the neck and the superior mediastinum. Survival exceeding 20 months was observed in three patients. Complete neck tumor response was observed in five patients, among whom four had undergone previous operations. No response was seen in distant metastases, which were the cause of death in 14 patients. These treatment modalities are effective in some patients, both in terms of survival and of local control, avoiding death from local invasion. Gross tumor resection should be performed whenever possible but should not delay the commencement of this protocol. Toxicity was high and remains the main limiting factor. 