Metastatic differentiated thyroid cancer: worst prognosis in patients with metachronous metastases

PURPOSE: To describe the overall survival and progression-free survival in patients diagnosed with differentiated thyroid carcinoma with synchronous and metachronous metastatic involvement. MATERIALS AND METHODS: A retrospective cohort study was conducted with 101 patients with differentiated thyroid cancer (DTC) who had metastatic involvement at diagnosis or during follow-up, who were treated at the National Cancer Institute between January 1, 2010 and December 31 of 2015. RESULTS: 81 patients (80.2%) were women and the mean age at diagnosis was 49 years (12–80). Synchronous metastases were detected in 54.5% of patients and metachronous metastasis was diagnosed in 45.5% of patients, in whom the mean time between initial diagnosis and the finding of distant metastases was 5 years. Pulmonary involvement occurred in almost all patients, with (131)I uptake in 58% of synchronous metastases and in 21% of metachronous. There were 10 events in the patients with (131)I-avid metastases with a median time to progression that was not reached, and there were 23 events in patients with (131)I-refractory metastases with a median time to progression of 96 months; The median time to progression was significantly longer in patients with synchronous metastases compared to those with metachronous metastases (Not reached vs 95 months, P = 0.017) The 5-year overall survival rate was 95% to the entire cohort. CONCLUSIONS: The present study contributes to the expansion of the knowledge about this clinical course of DTC with the finding of a worst prognosis in patients with metachronous metastases.