Survival and Prognostic Factors in Patients with No Less than Three Distant Organ System Metastases from Differentiated Thyroid Carcinoma

1529 Objectives: For patients with differentiated thyroid carcinoma (DTC), distant metastases are commonly identified in the lungs and bones. However, they are relatively rare in other distant organs, such as the liver, kidneys or brain. The aim of the current study was to describe the clinical outcomes and evaluate the prognostic factors of patients with no less than three different distant organ system metastases from DTC. Methods: This study retrospectively identified 717 patients diagnosed with DTC with distant metastases between January 2005 and December 2017. The 5-year and 10-year overall survival (OS) rates were calculated by the Kaplan-Meier methods and Cox proportional hazards. Results: Among the 717 participants, 37 (5.16%) patients had no less than three different distant organ system metastases from DTC. Thirteen patients had no radioactive iodine (RAI) avidity. Meanwhile, 25 patients were diagnosed as refractory to radioactive iodine therapy from differentiated thyroid carcinoma (RAIR-DTC). The 5-year and 10-year OS rates of patients with no less than three different distant organ system metastases from DTC were 45.95% and 37.84%, respectively. RAI avidity and RAIR-DTC were main independent prognostic factors influencing both the 5-year and 10-year OS rates. Conclusions: Patients with no less than three distant organ system metastases from DTC had poor prognosis. RAI avidity and RAIR-DTC were main factors influencing clinical outcomes for patients with no less than three different distant organ system metastases from DTC.