[Treatment outcomes and prognostic analysis of 882 cases of poorly differentiated/anaplastic thyroid carcinoma in China: a multicenter study].

Objective: To analyze the current status of diagnosis, treatment and prognostic factors of poorly differentiated thyroid carcinoma (PDTC) and anaplastic thyroid carcinoma (ATC) using a multicenter cohort database. Methods: A retrospective analysis was performed on clinical data of 882 patients with PDTC/ATC who received treatment from 14 centers between January 2016 and June 2025. There were 346 cases of PDTC and 536 cases of ATC, including 424 cases of conventional ATC (con-ATC) and 112 cases of coexisting papillary and anaplastic thyroid carcinoma (co-PTC/ATC). Demographic, clinicopathologic, and treatment and follow-up data were collected. Kaplan-Meier method was used to plot survival curves, and Cox proportional hazards regression model was applied to evaluate the factors influencing overall survival (OS). Results: This cohort included 514 females and 368 males. 74.72%(659/882) of the patients were over 55 years. At the time of diagnosis, the tumors frequently invaded vital adjacent structures, with 58.28% (514/882) of patients presenting with stage T3b-T4b disease. Distant metastases were observed in 27.66% (244/882) of patients, most commonly involving the lungs (78.28%, 191/244). The median OS of con-ATC patients was 8.0 months (95%CI: 7.0-10.0). The median OS of co-PTC/ATC patients was 36.0 months (95%CI: 18.0-65.0), that of PDTC patients was 104.0 months (95%CI: 72.0-NA). Patients who underwent surgery as the initial treatment appeared to have prolonged survival compared with those receiving systemic therapy (surgery 36.0 months (95%CI: 28.0-57.0) vs systemic therapy 12.0 months (95%CI: 9.0-17.0): HR (95%CI)=1.342 (1.100-1.637), P=0.004). Among patients who underwent R2 resection followed by adjuvant radiotherapy, OS did not differ significantly from that of patients who achieved R0 or R1 resection (R0/R1 resection 44.0 months (95%CI: 32.0-65.0) vs R2 resection followed by adjuvant radiotherapy 25.0 months (95%CI: 18.0-46.0): HR (95%CI)=0.860 (0.654-1.131), P=0.279). For patients with unresectable PDTC/ATC, combined targeted therapy and immunotherapy were associated with superior overall survival compared with other systemic treatment regimens (combined targeted therapy and immunotherapy 13.0 months (95%CI: 9.0-27.0) vs other systemic treatment regimens 9.0 months (95%CI: 6.0-16.0): HR (95%CI)=0.681 (0.495-0.936), P=0.018). Conclusions: Long-term survival is achievable in selected patients with PDTC/ATC through active multimodal treatment. When formulating treatment strategies, radical surgery should be considered as the key to cure.