Long-term outcome of lobar ablation in differentiated thyroid cancer (DTC)

Objectives Purpose of this study was to compare the outcome of patients treated with radioiodine for lobar ablation(LA) after hemithyroidectomy(HT) versus those underwent completion thyroidectomy(CT) followed by remnant ablation

Methods A retrospective study was done in 737 HT patients with DTC. LA with radioiodine was done in 365(PCT=285, FCT=80), while CT followed by remnant ablation in 373(PCT=292, FCT=81) patients. All patients were put on T4 suppression, re-evaluated 6 monthly and treated with more doses when needed. Annual follow up done by thyroglubulin assay for recurrence. Further evaluation and treatment done as required

Results Mean 24 hours uptake was 13.7±0.92% in LA and 4.7±0.53 % in CT group. Successful ablation at first dose of LA was 73% and 92% in second dose. Whereas single dose ablation in CT group was 93%(P=0.03). If we consider the first dose of LA as an alternative to second surgery, then the rates of successful ablation were same in both groups (P=0.899). Mean activity given at first dose was 39.8±2.69 mCi in LA and 45.4±2.77 mCi in CT. Cumulative activity in LA was 63.44±12 mCi and 52.74±5.13 mCi in CT(P=0.346). There was 12 (3.28%) recurrence in LA group ( nodal 5, local 3, pulmonary 2, skeletal 2) within median follow up period of 5 years(range 1-25 years) and 7(1.78%) recurrence in CT group( nodal 3, local 1, pulmonary 1, skeletal 2) within median follow up period of 5 years(range 1-21years). Difference in recurrence rate was not statistically significant (P=0.238)

Conclusions No statistically significant difference noted between lobar ablation and completion thyroidectomy in terms of ablation rate and long term outcome