Complete thyroidectomy was recommended for patients with well-differentiated thyroid carcinoma to remove any potential residual contralateral cancer tissue and to facilitate detection of metastatic lesions by radioactive iodide (131I). Unfortunately, 8-32% incidence of severe complications were noted after reoperation. At present, there are still not enough data about the ablative effect of 131I for such conservative surgical treatment of well-differentiated thyroid cancers. The major goal of the present study was to examine the effects of 131I for ablation of thyroid remnants in order to obviate the severe complications associated with reoperation. From January 1977 to December 1995, 210 papillary or follicular thyroid carcinoma patients received subtotal thyroidectomy or lobectomy. After the operation, 46 of the 210 patients received 131I for remnant ablation. At doses of ≥30 mCi 131I, 38 thyroid remnants were successfully ablated; 25 of 38 (65.8%) patients successfully ablated patients received 30 mCi 131I one-four times. Five patients expired during the follow-up period, including two follicular carcinoma patients who were misinterpretated as having benign lesions in the first operation. Patients in the overall failure versus success group for thyroid remnant ablation revealed increased age, histopathology of follicular carcinoma, higher postoperative 131I uptake in the neck bed, higher postoperative thyroglobulin levels, bigger tumor size, and higher mortality. In conclusion, repeated 30 mCi 131I treatments were adequate for most thyroid remnant ablations following subtotal thyroidectomy or lobectomy in well-differentiated thyroid cancer patients. Misinterpretation of follicular cancer as benign lesions and unresectable tumor comprised the main reasons for mortality.
From the Division of Endocrinology and Metabolism, Department of Internal Medicine (J.D.L., M.J.H., H.F.W.), Department of Surgery (T.C.C.), and Department of Nuclear Medicine (K.Y.T.), Chang Gung Memorial Hospital, Taiwan, R.O.C.
Address correspondence and reprint requests to Dr. Jen-Der Lin, Division of Endocrinology and Metabolism, Chang Gung Memorial Hospital, 5, Fu-Shin St. Kweishan county, Taoyuan Hsien, Taiwan, R.O.C.