Radioiodine Therapy of Metastases From Carcinoma of the Thyroid: A Six-Year Progress Report*§

IN the past six years, 30 patients with metastases from carcinoma of the thyroid have been studied by our group at Montefiore Hospital. Of these, 12 were treated with radioactive iodine. On admission every patient was given a tracer dose of radioiodine and checked with a Geiger counter for uptake in the metastases. However, our cumulative experience shows that in the presence of normal non-neoplastic thyroid tissue the metastases do not usually show uptake. For patients with a proven diagnosis of metastatic carcinoma of the thyroid we now regard radiation or surgical thyroidectomy as a basic first step in treatment. In this manner, uptake can be induced in the metastases of most patients. After uptake has been demonstrated, the patient is treated with multiple large doses—usually 100 millicuries or more—of radioactive iodine (I131). In June 1947 we reported the first successful induction of uptake of radioiodine in metastases from thyroid carcinoma. This was accomplished by thyroidectomy (surgical or radiation) or by injection of exogenous thyroid stimulating hormone (T.S.H.) (1, 2). Thyroidectomy increases the T.S.H. production in the pituitary and removes the competition of the thyroid gland for both the T.S.H. and the iodine, thus enabling the tumor tissue to take over the function of the normal gland to varying degrees. This effect of thyroidectomy on the function of metastatic thyroid carcinoma was later confirmed by Rawson et al. (3).