Clinical Outcome by AMES Risk Definition in Japanese Differentiated Thyroid Carcinoma Patients

This study aimed to analyse whether age, metastasis, extrathyroidal invasion and size (AMES) risk definition is valuable for Japanese patients with differentiated thyroid carcinoma (DTC). Methods: Two hundred and fifteen Japanese DTC patients (43 men, 172 women; mean age, 51.0 years; mean follow-up, 102 months) treated surgically at our institutions between 1981 and 2001 were retrospectively analysed. Clinicopathological features were compared between high-risk and low-risk patients by AMES criteria. Various risk factors were also evaluated for each group of patients. Results: There were 57 high-risk and 158 low-risk patients. Recurrence and mortality rates were 43.9% and 24.6% in high-risk patients and 7.6% and 0.6% in low-risk patients, respectively (p < 0.0001). Disease-specific survival rates at 5, 10 and 15 years were 84.3%, 74.0% and 63.5% in high-risk patients and 100%, 100% and 98.3% in low-risk patients, respectively (p < 0.0001). Univariate analysis revealed that curative resection, local recurrence and distant metastasis were risk factors for mortality in the high-risk group. Multivariate analysis revealed that curative resection (hazard ratio [HR], 4.68; 95% confidence interval [CI], 1.23-17.83; p = 0.024) and distant metastasis (HR, 4.79; 95% CI, 1.24-18.40; p = 0.023) were significantly related to mortality in high-risk patients. Conclusion: AMES can identify high-risk and low-risk Japanese patients. Distant metastasis and curative resection are prognostic factors for disease-specific death.