Long Term Outcomes of Patients Undergoing Ablation With Low Activities of RAI.

The standard treatment of differentiated thyroid carcinoma (DTC), namely papillary and follicular thyroid carcinoma (PTC and FTC) is total thyroidectomy followed, when appropriate, by radioiodine therapy. The rationale of this treatment resides in the early recognition of persistent/recurrent disease and in the decrease of locoregional recurrence. Historically, thyroid remnant ablation was performed in hypothyroidism, after 4 weeks of thyroid hormone withdrawal (THW), to achieve an optimal radioiodine uptake. After the introduction in the clinical practice of recombinant human TSH (rhTSH) several studies demonstrated that the preparation with rhTSH was equivalent to THW when using high activities (100 mCi) of radioiodine. More recently, many studies demonstrated that the same rate of ablation could be achieved with low activities of radioiodine (30 mCi) using rhTSH preparation. However, due to the relatively short term follow up of all these studies (2 to 5 years), until recently, the long term outcome of patients undergoing thyroid remnant ablation with low activities of radioiodine and rhTSH preparation was only presumed to be comparable to low activities and THW preparation. To address this point a recent Italian study investigated the outcome of a cohort of patients treated 10 years before with low activities of radioiodine and prepared either with THW and rhTSH. This study demonstrated that the long term outcome of these groups was comparable. To confirm the results of this study we await the results of the long term outcome of two large, randomized, multicenter studies recently published by French and English authors.