Abstract: Background and purpose: Anaplastic thyroid carcinoma (ATC) is a rare but highly aggressive malignancy with poor prognosis, and there is no standardized therapeutic regimen. The aim of the study was to analyze the prognostic factors influencing survival of the patients with ATC, and to explore the reasonable treatment methods. Methods: The sociodemographic and clinicopathologic characteristics of 37 ATC patients at the Department of Head and Neck Surgery in Gansu Provincial Cancer Hospital between May 2008 and May 2014 were analyzed retrospectively. The Kaplan-Meier method and log-rank test were used to determine and compare the survival. Potential prognostic factors were identified by univariate and multivariate Cox regression analyses. Results: Females were more affected. Twenty-five cases occurred in women, and 12 in males. The age range was 42-82 years, and the median age was 64. ATC accounted for 5.3% of all thyroid cancers in this study, and goiter was present in 29.7% of patients with ATC. Less than 20% of the ATC patients lived in urban areas, and more than half lived in endemic goiter areas. Mean survival time was 11.5 months. Median survival time was 5.9 months, and half-, 1- and 2-year overall survival rates were 48.6%, 21.6% and 13.5%, respectively. Univariate analysis showed that age, goiter, distant metastasis, surgery, comprehensive therapy and postoperative radiotherapy were independent prognostic factors of survival in all ATC patients. Multivariate analysis showed that age no more than 50 years (HR=0.21, 95% CI: 0.06-0.77, P=0.019), surgery (HR=0.15, 95% CI: 0.04-0.59, P=0.007) and comprehensive therapy (HR=0.31, 95% CI: 0.11-0.85, P=0.023) were independent protective factors associated with the survival of ATC patients. With regard to operated patients，macroscopic residual tumor (HR=7.98, 95% CI: 1.38-46.21, P=0.020) and distant metastasis (HR=6.26, 95% CI: 1.65-23.83, P=0.007) were independent risk factors of survival. Postoperative radiotherapy (HR=0.18, 95% CI: 0.04-0.83, P=0.028) was a protective factor. Conclusion: Age, type of surgery resection and postoperative radiotherapy influence prognosis of ATC independently. The patients with ATC may have a better prognosis by receiving multidisciplinary comprehensive therapy combining surgery and postoperative radiotherapy with or without chemotherapy based on each individual circumstance.

Key words: Anaplastic thyroid cancer, Prognosis, Factor analysis, Survival, Treat methods