Can Age at Diagnosis and Sex Improve the Performance of ATA Risk Stratification System for Prediction of Structural Persistent and Recurrent disease in Patients with Differentiated Thyroid Carcinoma? A Multicenter Study

Abstract

Objective: Despite age at diagnosis has been suggested as a major determinant of disease-specific survival in the recent TNM staging system, it is not included in the recent American Thyroid Association (ATA) guidelines to estimate the risk of recurrence. Nevertheless, the effect of sex on DTC recurrence is controversial. Therefore, this multicenter study was conducted to assess whether age at diagnosis and sex can improve the performance of the ATA three-tiered risk stratification system in DTC patients with at least five years of follow-up.

Methods: In this study, the computer-recorded data of the patients diagnosed with DTC between January 1985-January 2016 were analyzed. Only patients with a proven structural persistent/recurrent disease were selected for comparisons.

Results: This study consisted of 1691 patients (1367 females) with DTC. In Kaplan-Meier analysis, disease-free survival (DFS) was markedly longer in females only in the ATA low-risk category (p=0.045). Nevertheless, a markedly longer DFS was observed in patients <45 years old in the ATA low and intermediate-risk categories (p=0.004 and p=0.009), while in patients <55 years old, DFS was markedly longer only in the ATA low-risk category (p <0.001). In Cox's proportional hazards model, age ≥45 and ≥55 as well as ATA risk system were all independent predictors of persistent/recurrent disease.

Conclusions: Applying the age cut-off of 45 in the ATA intermediate and low-risk categories may identify patients at higher risk of persistence/recurrence and may improve the performance of the ATA risk stratification system while sex may only improve the performance of ATA low-risk category.