biostudies-literatureUnknown16Guo Y<h4>Objective</h4>Poorly differentiated thyroid cancer (PDTC) is a rare, heterogeneous carcinoma from follicular cells, characterized by poor differentiation, aggressive spread, and poor prognosis. Currently, there is no specific staging system for PDTC. This study aimed to develop a new TNM staging system tailored to PDTC for improved disease management.<h4>Methods</h4>A new TNM staging system was designed and internally validated using data from the US SEER database (2004-2016) on PDTC cases. External validation was performed using data from four major institutions in China. Prognostic factors influencing cancer-specific survival (CSS) were identified through Cox regression analyses. Patients were stratified into subgroups based on adjusted hazard ratios (AHRs), weighted by these prognosFrontiers in endocrinology1586542https://www.ebi.ac.uk/biostudies/studies/S-EPMC12401677biostudies-literatureDevelopment of a new TNM staging system for poorly differentiated thyroid carcinoma: a multicenter cohort study.PMC12401677Guo LZhong QWu LGuo YZhuang SJia CXie LWang XYang ALiu TPeng JPang FfalseDevelopment of a new TNM staging system for poorly differentiated thyroid carcinoma: a multicenter cohort study.<h4>Objective</h4>Poorly differentiated thyroid cancer (PDTC) is a rare, heterogeneous carcinoma from follicular cells, characterized by poor differentiation, aggressive spread, and poor prognosis. Currently, there is no specific staging system for PDTC. This study aimed to develop a new TNM staging system tailored to PDTC for improved disease management.<h4>Methods</h4>A new TNM staging system was designed and internally validated using data from the US SEER database (2004-2016) on PDTC cases. External validation was performed using data from four major institutions in China. Prognostic factors influencing cancer-specific survival (CSS) were identified through Cox regression analyses. Patients were stratified into subgroups based on adjusted hazard ratios (AHRs), weighted by these prognos2025-01-01T00:00:00Z20252026-05-29T22:12:53.313Z2026-05-18T03:07:33.459ZS-EPMC124016774090480510.3389/fendo.2025.1586542