Endocrine Abstracts

Introduction: Papillary thyroid carcinoma (PTC) is the most common type of differentiated thyroid cancer, accounting for about 80% of all cases of thyroid cancer. 20 – year survival rate is about 90%. However, PTC can be aggressive – up to 30% of the patients have local renewal or systemic spread.

Our objective was to evaluated the clinicopathological factors of recurrence in completely resected PTC patients.

Methods: A retrospective review of a prospectively maintained thyroid cancer database was performed. Study included 102 patients with histopathologic diagnosis of PTC, treated at Hospital of Lithuanian University of Health Sciences, Kaunas clinics between 2004 and 2017. Patients were divided into: remission group – patients who had no recurrences for at least 1 year after total thyroidectomy and postoperative I¹³¹ therapy; recurrence group – patients who had local or systemic tumour recurrences for at least 1 year after total thyroidectomy and postoperative I¹³¹ therapy. Multivariate analyses were performed to identify predictive factors of PTC recurrence patterns. Descriptive statistics was performed, Student´s t test or Mann-Whitney U test for independent samples, Chi-Square for qualitative data.

Results: Study included 51 patients in each group. Average age at diagnosis was 63.51 ± 6.47 years in remission and 53.16 ± 15.6 years in recurrence group (P < 0.001). The higher rate of recurrence was statistically significant among younger than 55 years old patients (P < 0.001). There was no significant difference between gender, multifocality, Hashimoto’ thyroiditis and rate of PTC recurrence (P > 0.05). Most common histologic type of recurrence was classic PTC 80.5% (n = 33) (P < 0.001). Classic PTC histology was associated with greater incidence of AJCC tumour stage and lymph node metastasis (P < 0.001).

Conclusion: This analysis included comparison of the associations between clinicopathologic factors, histological sub-types and recurrences of PTC. We found evidence that younger age and classic PTC sub-type is associated with increased recurrence rate of PTC. Our study lend support to recent data indicating that classic PTC confers a worse prognosis. But further studies are also warranted to expand upon our findings.