Multifocality and Hashimoto’s thyroiditis as independent predictors of structural recurrence in a cohort of low risk intrathyroidal papillary thyroid cancer.

Abstract

e17577 Background: Increasing incidence of thyroid malignancies is almost totally attributable to papillary thyroid cancer (PTC). Although all disease stages are involved, PTCs confined to the thyroid were those with the higher trend. The absence of dedicated randomized controlled trials makes challenging the management of these low risk PTC at different steps of the therapeutic process (extent of surgery, prophylactic central node dissection, and radio-iodine treatment). Thus, it is mandatory to set a prognostic system suitable for this clinical setting. We analyzed prognostic factors of structural recurrence in a large cohort of consecutive low-risk intra-thyroidal PTC. Methods: Multicenter retrospective study including pT1/2 PTC without any evidence of extra-thyroidal disease. The following parameters were considered: gender, age at diagnosis, histology, tumour size, multifocality, pathologically-proven Hashimoto’s thyroiditis (HT), and radiometabolic treatment (RAI). The parameters significantly associated with structural recurrence at the univariate analysis ( p < 0.05) were included in the multivariate analysis. Results: We included 284 patients (mean follow-up 6.3 yrs). At univariate analysis, parameters achieving significance were: age at diagnosis ≥ 45 yrs (p = 0.001, OR 0.04, 95% CI 0-0.72), microcarcinoma (p < 0.001, OR 0.02, 95% CI 0-0.39), multifocality (p < 0.001, OR 4.3, 95% CI 1.88-9.84), HT (p = 0.018, OR 0.33, 95% CI 0.13-0.86), and RAI (p = 0.002, OR 19.43, 95% CI 1.16-323.3). At multivariate analysis, only multifocality (p = 0.042, OR 2.52, 95% CI 1.03-6.16) and HT (p = 0.036, OR 0.34, 95% CI 0.12-0.93) revealed as independent prognosticators. Conclusions: Our data show that multifocality and HT should be considered as the main parameters for the decision-making of low risk PTC. Further studies are required. Note: We acknowledge Umberto Veronesi Foundation for granting Vincenzo Marotta with Post-doctoral Fellowship year-2017 Award.