A prospective clinical trial to assess the efficacy of radioiodine ablation as an alternative to completion thyroidectomy in patients with differentiated thyroid cancer undergoing sub-total thyroidectomy

Abstract

We conducted a prospective clinical trial to evaluate whether radioiodine ablation can be an effective alternative to completion thyroidectomy in patients undergoing sub-total thyroidectomy and if yes, the optimum activity of 131I and frequency of ablation. A total of 85 patients (F-63; M-22) with mean age of 37.9 ± 12.3 years were recruited in this study. The pre-ablation mean 24 hour radioiodine neck uptake, effective half-life, residual thyroid tissue weight and TSH values were 13.9 ± 8.5%, 4.5 ± 0.9 days, 9.6 ± 3.6 g and 11.7 ± 6.4 μIU/ml, respectively. Thyroid tissue was completely ablated in 50 patients (58.8%, 95% CI:50-68%) after mean 1st administered activity of 32.3 ± 10.7 mCi of 131I and the cumulative ablation rate was 91.8% after two doses of 131I. During mean follow-up duration of 49 months no local/distant recurrence has been observed so far in this cohort. It appears that radioiodine ablation may be an attractive alternative to completion thyroidectomy and an activity as low as 35 mCi may achieve reasonable ablation. © 2006 Taylor & Francis.