The efficacy of radioiodine remnant ablation for differentiated thyroid carcinoma patients with an incomplete thyroidectomy

BACKGROUND: The aim of this study was to evaluate the efficacy of radioiodine remnant ablation (RRA) for differentiated thyroid carcinoma (DTC) patients with an incomplete thyroidectomy. METHODS: The medical histories of postsurgical DTC patients who accepted RRA between 2010 and 2012 were retrospectively reviewed. Among them, 113 patients who had undergone a total or near-total thyroidectomy comprised the complete thyroidectomy group (CT group) and the remaining 40 patients who had undergone a lobectomy or sub-total thyroidectomy comprised the incomplete thyroidectomy group (ICT group). The difference in the patients' age, gender, histology, serum TSH level and 24hr radioactive iodine uptake (RIU) between the two groups was analyzed by chi(2) Test or ANOVA. The efficacy of RRA in ICT group was evaluated by comparing its rate of complete ablation after the first RRA and its cumulative rate of complete ablation after the second RRA to the rate of complete ablation after the first RRA in CT group respectively by chi(2) Test. RESULTS: Of all the clinical characteristics, only serum TSH level and 24hr RIU have significant difference between two groups (P<0.01 for both). The rate of complete ablation after the first RRA was 67.26% in CT group. The rate of complete ablation after the first RRA and the cumulative rate of complete ablation after the second RRA was 27.50% and 67.50% respectively in ICT group. The ablative rate of the first RRA between the two groups was compared by chi(2) Test and the difference was significant (P<0.01). The ablative rate of the first RRA in CT group was compared with the cumulative rate of the second RRA in ICT group and the difference was not significant (P=0.978). CONCLUSIONS: Although the efficacy of RRA in DTC patients with an incomplete thyroidectomy is not as good as that of patients with a complete thyroidectomy after the first RRA, a higher ablative rate can still be achieved after the second or third RRA.