The success rates of initial I-131 ablation in differentiated thyroid cancer: Comparison of less-strict and very-strict low-iodine diets

Objectives To compare the success rates of radioiodine ablation therapy according toless-strict and very-strict low-iodine diets (LID).

Methods The success rates of postsurgical radioiodine ablation in differentiated thyroid carcinoma patients receiving empiric dose of 150 mCi were retrospectively reviewed. First-time radioiodine ablation therapy in 71 patients following less-strict LID and 90 patients following very-strict LID were analyzed. Less-strict LID restricted seafood, iodized salt, egg yolk, bread, and multi-vitamin. Very-strict LID restricted additional food items such as fresh water fish, rice, soy bean, milk, butter, spinach and broccoli. Radioiodine ablation therapy was considered successful when follow-up I-123 whole body scan was negative and stimulated serum thyroglobulin level was less than 2.0 ng/ml.

Results The success rate of patients following less-strict LID was 80.3%, and very-strict LID was 75.6%. There was no statistically significant difference in the success rates (p=0.48).

Conclusions The success rates between patients following less-strict and very-strict LID showed no difference. Very-strict LID may not contribute to improving the success rate of initial radioiodine ablation therapy at the cost of great inconvenience to the patient.