An analysis of "ablation of thyroid remnants" with I-131 in 511 patients from 1947-1984: experience at University of Michigan.

Between January 1947 and June 1983, 511 patients were given treatment doses of I-131 after surgery for thyroid cancer in the presence of I-131 uptake in thyroid remnants. Thirty-four patients were removed from the study leaving 462 patients with a 99% follow-up at 1 or more yr, with a mean follow-up of 15 yr. Of 267 patients with radioiodine uptake confined to the thyroid bed, 233 (87%) had ablation from the first dose of I-131 ranging from 100 to greater than 200 mCi. The higher the percent uptake, the more difficult it was to achieve ablation. In the percentages of successful ablation, there were no significant differences between I-131 doses of: 100-149 mCi, 150-174 mCi, 179-199 mCi, and 200 mCi or more. The 100-149 mCi ablative dose may furnish "adjuvant" therapy for occult metastases.