Patient Age Is an Independent Risk Factor of Relapse of Differentiated Thyroid Carcinoma and Improves the Performance of the American Thyroid Association Stratification System

Abstract

Background: The 2015 American Thyroid Association (ATA) guidelines proposed a three-category system for estimating the risk of recurrence of differentiated thyroid carcinoma (DTC). This system includes several perioperative features, but not age at diagnosis. However, age has traditionally been recognized as a critical factor in the survival of DTC patients, and the eighth edition of TNM stated that patients older than 55 years were at higher risk of death. In this study, we raised the question of whether age at DTC diagnosis impacts on its risk of recurrence. Specifically, the present study aimed to (i) evaluate the association between age at diagnosis and structural recurrence and (ii) investigate whether age at diagnosis could improve the performance of the ATA system. Methods: During the study period, four institutions selected DTC patients treated with both thyroidectomy and radioiodine and who had follow-up for at least one year. Patients with proven structural evidence of disease during follow-up were identified, and disease-free survival (DFS) was calculated accordingly. Results: The study involved 1603 DTC patients with a median age of 49 years and DFS of 44 months. Disease recurred in 8%. The shortest DFS was found in the oldest patients. The Kaplan-Meier curves were calculated for each decade of age, and there was a significant association with DFS ( p = 0.0014). Patients older than 55 years had significantly higher risk (hazard ratio [HR] 1.78, 95% confidence interval ). The Kaplan-Meier curves of DFS in high-, intermediate-and low-risk groups showed a significant association only in the high-risk group ( p = 0.0058). Patients older than 55 years had significantly higher risk of relapse over time only in the high-risk group ). Cox's proportional analysis showed that the age cutoff of 55 years and the ATA system were significant predictors of relapse. Adding age at diagnosis above 55 years to the ATA system identified a subgroup of patients at highest risk for relapse. Conclusions: The age threshold adopted in the eighth edition of TNM staging system for DTC patients' prognosis also identifies cases at higher risk of relapse. Applying age at diagnosis, with a cutoff of 55 years, to the ATA risk stratification system identifies cases at highest risk of relapse.

Analysis of risk factors and prognosis in differentiated thyroid cancer with focus on minimal extrathyroidal extension

“…Interestingly, age > 55 years was not significantly associated with a higher risk for disease. This is in contrast to a prior study by Trimboli et al [ 27 ], who showed that high-risk patients (as stratified by ATA criteria [ 28 ]) older than 55 years had the highest risk for relapse and significantly shorter disease-free survival. A possible explanation is the assumably small number of high-risk patients, as patients with tumors showing macroscopic ETE were not included, and the generally smaller sample size.…”

Survival in differentiated thyroid carcinoma: Comparison between the 7th and 8th editions of the AJCC/UICC TNM staging system and the ATA initial risk stratification system

“…Conversely, the ATA IRSS was designed to stratify the DTC patients according to the risk of tumor progression, instead of the death of the disease 3,8 . As the relationship between the events is unquestionable, 3,11,12 TNM has also been frequently used in clinical practice to assess the risk of cancer recurrence and to guide treatment and follow‐up 11 …”

“…Relapses, in turn, affect survival with mortality rates reaching more than 10% if locoregional disease and if an incomplete response to additional treatment is found, 9 escalating to 55% with the development of distant metastases 3,10 . Therefore, disease‐free survival (DFS) has been considered a better predictor of outcome than overall survival (OS), as the death of the disease can actually happen decades after the tumor diagnosis 11,12 . In clinical practice, nonetheless, the applicability of TNM system for recurrence prediction has been suggested 13,14 …”

WITHDRAWN: The Clinical and Prognosis Value of the Number of Metastatic Lymph Nodes in Papillary Thyroid Carcinoma Patients

“…Old age is a risk factor for poor prognosis of PTC patients [15,20] and a recent AJCC TNM staging system used a 55-years cutoff to upstage patients. Whereas Jeon et al [21] reported that patients aged ≥45 years were at a higher risk of LNM; other studies revealed that young people are also more likely to have LNM [22].…”