Abstract: Objective To compare the clinicopathological characteristics and survival outcomes of elderly(≥60 years old) and younger(<60 years old) patients with anaplastic thyroid cancer(ATC).Methods The information about clinicopathological characteristics and prognostic in patients with diagnosed ATC was from 1998~2016 was extracted from the Surveillance,Epidemiology,and End Results(SEER) database.A total of 516 eligible patients and divided into the elderly group(n=391) and the younger group(n=125).Compared the clinicopathological characteristics between the two groups by using chi-square test.The Kaplan-Merrier and Cox regression methods were used to determine the prognostic factors of ATC.Finally,analyzed the mortality risk of two groups in the tumor staging subgroups.Results The younger group was more likely to receive radiotherapy(75.9% vs.55.5%) and chemotherapy(66.7% vs.39.5%).In addition,the specific survival rate and overall survival rate of young patients were significantly higher(P<0.05).Multivariate Cox regression analysis revealed that age<60-years-old was significantly associated with the better prognosis（OS:HR=0.69,95%CI=0.56~0.86,P=0.001;CSS:HR=0.73,95%CI=0.59~0.92,P=0.007）.And age<60-year-old was an independent predictor of prognosis in ATC patients with distant metastasis.Conclusion The prognosis of elderly ATC patients is worse than that in younger patients and age may be a prognostic factor for anaplastic thyroid cancer.

Key words: anaplastic thyroid cancer, SEER database, age, comparison