Background: Malignant hemangioendotheliomas of the thyroid are rare tumors predominantly seen in areas with endemic goiter such as the Alpine regions. The estimated incidence of the disease is between 0.15 and 0.25 per 100.000 inhabitants annually for Western Austria. The tumor is regarded as radio-resistant, and its prognosis is reported to be dismal.
Patients and methods: Between 1982 and 1999, 12 cases with immunohistochemically confirmed malignant hemangioendotheliomas of the thyroid were referred for postoperative or palliative treatment. There were 8 men and 4 women with a median age of 67 years (range, 55-81 years). With surgery, clear margins were achieved in 5, microscopic residues were left in 3, and gross residual disease in 3 patients. One patient had an inoperable primary tumor. Postoperative radiotherapy was given to 8 cases, 6 of them received the radiosensitizer razoxane on radiation days. Total tumor doses ranged between 54 and 65 Gy. Two patients with clear margins at surgery received no adjuvant radiotherapy and were observed only.
Results: Local tumor control was achieved in 11 of 12 patients; 5 lived longer than 5 years. The median survival time of all cases is presently 14 months (range, 0.5-196 months). If 3 cases with metastasis at diagnosis were left out of the analysis, the median survival is 70 months. Noteworthy is a complete regression of 2 lung metastases in a 72-year-old man treated with the combination of vindesine, razoxane, and radiotherapy; the patient is still in complete remission more than 94 months after 3-year maintenance therapy with vindesine and razoxane. Fibrinogen, factor VIII, and factor VIII-related antigen in the serum could serve as surrogate markers during the follow-up. The tolerance to the combined modality treatment was good to fair, local chemoradiation reactions of normal tissues have to be considered as the principal toxicity. It may also be of interest that 5 of 12 patients were exposed to vinyl chloride and other polymeric materials during their working life.
Conclusions: This small series indicates that the course of the disease is not uniformly bleak and that the resistance to radiotherapy reported in the literature has to be questioned. It appears that adequate surgery together with rapid radiation therapy in combination with razoxane, a radiosensitizer and agent that can normalize tumor blood vessels, is able to improve the local control rate and thus perhaps to alter the natural history of this disease. In addition, the data offer new evidence of the occurrence of vinyl-chloride-induced angiosarcomas outside the liver, and support similar observations that have already been published in case reports.