Medullary carcinoma of the thyroid in Norway. Clinical course and endocrinological aspects.

A study of the clinical, biochemical and histological findings of 57 patients with medullary thyroid carcinoma (MCT) in Norway, is presented. The diagnosis was established by light and electron microscopy and by measurements of immunoreactive calcitonin (iCT) in serum. The major factor influencing the prognosis was the extension of the disease at presentation. None of the 24 patients with tumour confined to the thyroid gland have died of the disease, and serum iCT was normal in 15 patients. Of 19 patients with regional lymph node metastes only 11 are alive 1 to 14 years after treatment, and of these 9 had increased serum iCt. 14 patients technically inoperable and/or with distant metastases, 12 have died of MCT, 1 are alive with elevated serum iCT. Of 14 patients with raised serum iCT, 8 have no clinical recurrence of the disease from 1 to 15 years after the operation. MCT-associated diseases were found in 8 patients, chronic thyroiditis in 10. Serum iCT was measured in 249 relatives of 42 patients, and abnormal elevations were found in 11 members of 6 families.