Endocrine Abstracts

Background and Aim: American Thyroid Association (ATA) guidelines do not consider age at diagnosis of differentiated thyroid cancer (DTC) as a prognostic factor in the estimation of risk of recurrence and persistent disease. While age at diagnosis has already been assessed in high-risk patients, it remains to be established whether there is a correlation between age at diagnosis and long term outcome in DTC patients.

Methods: We retrospectively evaluated 863 DTC patients with a median follow-up of 10 years, 52% of them classified as low risk (449/863) and 48% as intermediate risk (414/863). For each ATA-risk class patients were divided into subgroups based on age at diagnosis (<55 or ≥55 years).

Results: Age had no impact on clinical outcome of ATA low risk patients. Intermediate risk patients ≥55 years had a higher risk of recurrence (P = 0.0125), death (P = 0.013) and worse long term outcome (P = 0.006) at univariate analysis. Multivariate analysis confirmed the impact of age on mortality together with T stage in intermediate risk patients (OR= 5.35, 95% IC 1.44-25.55, P = 0.02 and OR=13.34, 95% IC 3.74-54.2, P < 0.01 for age and T stage, respectively). Age ≥55 years was the only independent risk factor associated with recurrences in intermediate risk patients (OR: 5.04, 95%IC 1.31-24.18, P = 0.02). Age at diagnosis was not confirmed as a long term outcome predictor at multivariate analysis in intermediate risk patients, where only T stage was significantly associated with final outcome (OR: 5.45, 95%IC 2.63-11.21, P < 0.001).

Conclusion: Age at diagnosis is a predictor of recurrence and death only in ATA intermediate risk patients. This finding suggests that age at diagnosis should be considered as an additional feature to improve the initial risk stratification.