Serum thyroglobulin and recurrent thyroid cancer.

Many thyroid malignancies are sufficiently differentiated to produce thyroglobulin both in situ and in perpipheral blood. Since patients who have undergone total thyroidectomy for malegnancy should not have normally circulating thyroglobulin, their serum thyroglobulin may provide a simple and specific tumour marker for recurrent disease. Of 30 such athyroid patients who were studied, all of the 20 patients who were disease-free ten years after thyroidectomy had minimal (less than15 ng/ml) serum-thyroglobulin levels while all of 10 patients with recurrences had raised levels (greater than 90 ng/ml). Controls ranged from 0 to 60 ng/ml. This assay should prove valuable in following patients who have undergone total thyroidectomy for recurrent thyroid malignancy.