Comparison of the prognostic value of AJCC cancer staging system 7th and 8th editions for differentiated thyroid cancer

Abstract

Background In the last American Joint Committee on Cancer/Tumor, Node, Metastasis (AJCC/TNM) 8th edition (TNM8), several changes were introduced to this risk stratification system to improve the prognosis of differentiated thyroid cancer (DTC). Aim To validate the impact of TNM8 vs. TNM 7th edition (TNM7) in DTC in terms of predictive value in two hospitals from Buenos Aires, Argentina. Methods Retrospective study of DTC patients from two institutions. Reclassification from TNM7 to TNM8, disease-specific survival (DSS), and final clinical outcomes at the end of follow-up (recurrent/persistent structural disease) (median 5 years) were analyzed. The proportion of variation explained (PVE) was used to compare the predictive capability of DSS of both classification systems. Results Reclassification of 245 patients, aged (mean ± SD) 55 ± 15.36 years, 91% women, to TNM8 from TNM7 showed: 82% vs 57% stage I (SI), 10% vs 8.5% SII, 5% vs 22% SIII, 3% vs 12% SIV (p < 0.01). Forty percent of the population was downstaged with TNM8. Ten-year DSS rates for SI, SII, SIII and SIV in TNM7 were 100, 100, 100 and 74%, respectively and in TNM8: 97.6, 100, 100 and 37.5%, respectively. Out of 4 disease-specific deaths in SIV TNM7, one was subclassified to SI TNM8, corresponding to a 53-year-old patient with structural persistence. PVE for TNM8 (29%) was more than twice that of TNM7 (13%). Conclusion In this Argentinian DTC patients sample, it was confirmed that the new TNM8 classification is more accurate in predicting survival attributable to cancer than its previous version.

Preoperative prognostic risk stratification model for papillary thyroid carcinoma based on clinical and ultrasound characteristics

“…progression is higher in younger patients compared to older patients (22). The eighth edition of AJCC staging uses 55 years as a threshold for stratification (8). Similarly, we used the same standard for subgrouping; however, the predicting value of age disappeared.…”

“…The clinical management of patients with PTC should be tailored to their specific condition according to the prognostic risk stratification (3). The 2015 American Thyroid Association (ATA) guidelines are generally used to predict disease-specific mortality (7), and the American Joint Committee on Cancer (AJCC)/TNM classification is used to predict the risk of disease recurrence or persistence (8). For differentiated thyroid cancer, the Age, Metastases, External infiltration, Size (AMES) system and the Metastases, Age, Completeness of resection, Invasion, Size (MACIS) system are used for predicting prognostic risk stratification (9).…”