Abstract
The incidence of papillary thyroid cancer (PTC) is rapidly growing, being the recorded increase mainly related to tumors <=2 cm. Small PTCs are generally considered low risk tumors and a less aggressive treatment has been proposed. Nevertheless, while a consensus has been reached for small tumors below 1 cm, some concerns exist about the treatment and follow-up of tumors comprised between 1 and 2 cm limited to the thyroid, previously staged as T2, and recently re-classified as T1 (AICC, 6th edition). In the present series, outcome and prognostic factors, including treatment options, have been evaluated in a series of 251 patients with PTC <=2 cm. All patients were treated by total thyroidectomy and radioiodine ablation was always performed when the tumor had an extrathyroidal extension. Persistence/recurrence or remission were evaluated by means of basal and rhTSH stimulated Tg levels, ultrasound examination and post-therapeutic radioiodine uptake. At univariate analysis, multifocality, non-incidentality, age >=45 years, tumor size >1 and <=2 cm, lymph nodal metastases at diagnosis and extracapsular invasion were significantly associated with persistent/recurrent disease. Interestingly, radioiodine ablation and central lymph-node neck dissection (CLND, VI level) were significantly associated with remission. At multivariate analysis, only multicentricity, lymphnodal metastases at diagnosis and extrathyroidal invasion were significantly associated with a poorer outcome. Of note, neither tumor size nor radioiodine treatment were associated with persistent/recurrent disease. Present data, obtained in a series of PTC <=2 cm, show that multifocal tumors and/or tumors with extrathyroidal extension are associated with persistent/recurrent disease confirming the need to perform radioiodine ablation in these cases. At variance, in unifocal tumors without extrathyroidal extension, radioiodine ablation might be avoided, regardless of tumor size. Finally, prophylactic CLND seems to be associated with a lower frequency of recurrence suggesting the need for prospective and randomized studies to evaluate its prognostic impact in recurrence.