Comparison of Different Staging Systems for Predicting Recurrence of Papillary Thyroid Carcinoma

ABSTRACT

BACKGROUND: Various staging systems for thyroid cancer that focus on cancer specific death have been suggested, but this approach had a limitation due to the relatively long clinical course and very low rate of cancer death. This study was performed to evaluate the staging systems and to determine the most predictive staging system for predicting recurrence. METHODS: The patients who underwent first total or near total thyroidectomy due to papillary thyroid cancer (PTC) at Asan Medical Center between January 1995 and December 2001 were the subjects of this study. The commonly used 8 staging systems were applied to these subjects. Disease free survival (DFS) and the relative importance of each staging system were determined by the Kaplan-Meier method, the Cox-proportional hazards model and the proportion of variation in the survival time explained (PVE). RESULTS: A total of 952 patients (M = 117, F = 835) were enrolled and their mean age was 45 years. During a median of 10 years of follow-up, 146 (15.3%) of 952 patients had recurred tumor. The independent prognostic factors were male gender, tumor size, extrathyroidal invasion and cervical lymph node metastasis. Risk stratification according to the American thyroid association (ATA) guideline was the most predictive staging system for recurrence of PTC (PVE 88.6%). The staging systems from EORTC (PVE 79.5%), and MACIS (PVE 68.4%) had significant values for predicting recurrence of PTC. The stage of NTCTCS could not predict recurrence (PVE 4.5%, P = 0.11). CONCLUSION: Risk stratification according to the ATA was most predictive staging system for predicting recurrence of PTC. The MACIS and EORTC staging systems have good value for predicting recurrence of PTC.