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A relook at the 8th edition of the AJCC TNM staging system of anaplastic thyroid carcinoma: A SEER‐based study
Author(s) -
Xiang Jingzhe,
Wang Zhihong,
Sun Wei,
Zhang Hao
Publication year - 2021
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/cen.14371
Subject(s) - medicine , stage (stratigraphy) , oncology , ajcc staging system , tnm staging system , anaplastic thyroid cancer , proportional hazards model , epidemiology , thyroid cancer , cohort , cancer , retrospective cohort study , thyroid carcinoma , anaplastic carcinoma , thyroid , staging system , paleontology , biology
Objective In the 8th edition American Joint Committee on Cancer (AJCC) tumour‐node‐metastasis (TNM) staging system (TNM‐8), changes have been made regarding anaplastic thyroid carcinoma (ATC) compared with the 7th edition (TNM‐7). The major changes are that anaplastic ATC now has the same T stage definitions as differentiated thyroid cancer, and new staging of IVA and IVB is implemented. However, the clinical impact of the new edition for ATC remains unclear due to scarce and conflicting data. In this study, we compared the AJCC TNM‐7 and TNM‐8 in the same group of patients. Design In this retrospective study, we included patients who were diagnosed with ATC between 2004 and 2015; data were gathered from the Surveillance, Epidemiology and End Results (SEER) database. Methods Overall survival (OS) was evaluated according to T stage and TNM stage according to the 7th and 8th editions. Kaplan–Meier and log‐rank testing was used to analyse OS. The effect of potential predictors was estimated using the Cox regression model. Results We included 669 patients in the study. The median age of the cohort was 70 years. During the follow‐up, 600 (89.7%) patients died, 528 of whom died of thyroid cancer. The TNM‐8 T staging more effectively predicted survival than the 7th edition (proportion of variation explained: 3.53% vs. 1.72%). However, the clinical stage was almost unchanged according to the TNM‐8 (proportion of variation explained: 10.69% vs. 10.73%). Conclusions The new T classification is an effective predictor of survival for patients with ATC. The results support the use of T definitions as per those of differentiated thyroid cancer. However, whether lymph node metastasis should be taken into account for defining ATC TNM staging should be reconsidered.