Endocrine Abstracts

An increasing prevalence of papillary thyroid carcinomas (PTC) of small size have been recorded in recent years. These tumors have a favorable outcome in most cases, and total thyroidectomy without radioiodine therapy is suggested for microcarcinomas (defined as ≤1 cm). The 6th edition of the TNM staging system for thyroid cancers includes in the T1 category tumors ≤2 cm, limited to the thyroid. Aim of the present study was to evaluate the clinical/pathological features and the outcome of 251 patients with PTC dividing them into 2 groups according to tumor size (A: ≤1 cm, n=156; B: >1≤2 cm, n=95). No differences between the 2 groups were observed in the mean follow-up (70±44.2 and 66±44.2 months), in the age at the diagnosis (47.5±13.7 and 44.7±16.2), in the gender (female in 68 and 61% of cases, respectively) and in the multicentricity (58 and 54%). A higher prevalence of incidentally discovered carcinomas was found in group A compared to group B (P<0.0001), while lymphnode metastases and extracapsular invasion at surgery were significant more frequent in group B (P=0.02 and P<0.0001, respectively). Concerning the outcome, no significant differences were found between the 2 groups, and in particular disease remission was observed in 90% of patients of group A and 84% of patients of group B. When multivariate analysis was applied to all tumors smaller than 2 cm, disease persistence/recurrence resulted to be associated with multicentricity, lymphnode metastases at diagnosis and extracapsular invasion (P=0.02, P=0.01, P=0.04, respectively), but not with tumor size.

In conclusion, T1N0 unicentric tumors has a favorable outcome independently from the tumor size (≤1 cm or >1 and ≤2 cm) and should be treated with a non-aggressive approach, avoiding radioiodine ablation.