Significance of the plasma calcitonin radioassay in the postoperative evaluation of patients with medullary thyroid carcinoma

In seven patients with medullary carcinoma the level of calcitonin (CT) was estimated by radioimmunoassay after thyroidectomy. Results were confronted with values obtained in healthy subjects. In three patients the level of CT was normal after operation, whereas singnificantly elevated levels were found in four patients. In all patients a gradual increase of plasma calcitonin was found in the postoperative period. In all these patients metastases were present. Reoperation and X-ray therapy was followed by a decrease of CT in blood plasma. These studies demonstrate the importance and usefulness of monitoring plasma calcitonin concentration in the follow up period of patients with medullary thyroid carcinoma. (author)