Low and Intermediate Risk Differentiated Thyroid Cancer: Predictive factors in the decision making to perform radioiodine (131I) ablation treatment.

Serum thyroglobulin (Tg), in the absence of Tg antibodies, is the most sensitive and specific marker of DTC persistence/recurrence. For this reason, in the international guidelines, there is much debate surrounding the choice of which patient should be submitted to postsurgical remnant radioiodine remnant ablation (RRA), particularly in low-risk (LR) and intermediate-risk (IR) differentiated thyroid cancer (DTC). Postoperative serum Tg and neck US are suggested for the first time to be considered in the decision making to submit the patient to RRA. We divided our project into 3 arms: 1) A retrospective study of a consecutive series of patients with unifocal micropapillary carcinoma (mPTC) treated with total thyroidectomy but not submitted to RRA in order to clarify the role of both Tg trend and neck US during the follow up; 2) A retrospective study of a consecutive series of low and intermediate risk DTC patients, in order to understand the role of both, the post-operative values of Tg measured on L-thyroxine therapy (LT4-HSTg), and postoperative neck US in the risk re-stratification and decision making to perform RRA, and to compare these parameters with the results of post therapeutic Whole Body Scan (ptWBS); 3) A prospective study to confirm the usefulness of the postoperative evaluation of both LT4-HSTg and neck US in the decision making to perform or not RRA in a consecutive series of patients with low and intermediate risk DTC treated in Pisa until September 2016.