Abstract:ObjectiveTo investigate the associations of clinical features and treatment with prognosis of anaplastic thyroid carcinoma（ATC）. Methods The clinical and follow-up data of 23 ATC patients admitted to Chongqing University Cancer Hospital from March 2012 to September 2019 were retrospectively analyzed. Results The median survival time of 23 ATC patients was 15 weeks. The 3-month survival rate, the 6-month survival rate and the 12-month survival rate were 56.5%, 39.1% and 30.4%,respectively. Univariate analysis showed that platelet count at admission, fibrinogen level and comprehensive treatment mode were the factors affecting the survival time of ATC patients(P＜0.05, P＜0.01）. Multivariate analysis showed that radiotherapy doses≥50 Gy, R0 or R1 resection+radiotherapy≥50 Gy were the favorable factors affecting survival outcome of ATC patients（P＜0.01,P＜0.05）. Conclusion The degree of malignancy of ATC is extremely high. R0 or R1 resection plus radiotherapy should be adopted as far as possible for ATC patients who have the opportunity of surgery. Radiotherapy may also achieve the similar effect for patients who have lost the opportunity of surgery.