Abstract

Differentiated thyroid cancer (DTC) has one of the most frequent diagnosed, especially among women and young adults. The DTC is represented by papillary (90%) and follicular forms (10%) with their multiple variants. The outcomes are generally very good, the recurrence rates are low and survival rates are excellent. Several staging system have been generated to inform DTC management. One of the most widely used is the tumor-nodes-metastasis (TNM) classification elaborated by the American Joint Committee on Cancer (AJCC), which allow to predict the risk of cancer-related death. Recently the 8^th edition of the AJCC staging system was published. The main changes with respect to 7^th edition are an increase in the age threshold for defining high risk of DC-related death (55 vs 44 years old) and a decrease in the unfavorable prognostic significance for some findings (i.e. microscopic extra-thyroidal extension). Consequently, also the management of DTC after surgery changed, reducing the treatment with radioactive iodine (RAI) adjuvant therapy only for patients with high risks. Some scientists in the world, endocrinologist and nuclear medicine, became to evidence strong differences of opinion about the guidelines recommendations continuing to use RAI adjuvant therapy. To reduce these discrepancies a joint statement was find between the more important four Society in the world to restore trust and confidence and a sense of collegiality between scientists and patients affected. However, there are still authors in the literature who continue to treat patients (except micro carcinoma) still with RIT. About 10 - 15% of patients need an additional dose of RIT to complete the ablation of thyroid residues, while in a small percentage of patients an activity may be present in the pulmonary region (diffuse or nummular type) while still more rare is the manifestation of secondary lesions in the bones or in other organs.

Keywords: Differentiated Thyroid Cancer (DTC); Tumor-Nodes-Metastasis (TNM); Radioactive Iodine (RAI)

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