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9886561 
Journal Article 
Defining a Valid Age Cutoff in Staging of Well-Differentiated Thyroid Cancer 
Nixon, IJ; Kuk, D; Wreesmann, V; Morris, L; Palmer, FL; Ganly, I; Patel, SG; Singh, B; Tuttle, RM; Shaha, AR; Gönen, M; Shah, JP 
2016 
Yes 
Annals of Surgical Oncology
ISSN: 1068-9265 
23 
2 
410-415 
English 
26215199 
BACKGROUND: Age 45 years is used as a cutoff in the staging of well-differentiated thyroid cancer (WDTC) as it represents the median age of most datasets. The aim of this study was to determine a statistically optimized age threshold using a large dataset of patients treated at a comprehensive cancer center.

METHODS: Overall, 1807 patients with a median follow-up of 109 months were included in the study. Recursive partitioning was used to determine which American Joint Committee on Cancer (AJCC) variables were most predictive of disease-specific death, and whether a different cutoff for age would be found. From the resulting tree, a new age cutoff was picked and patients were restaged using this new cutoff.

RESULTS: The 10-year disease-specific survival (DSS) by Union for International Cancer Control (AJCC/UICC) stage was 99.6, 100, 96, and 81 % for stages I-IV, respectively. Using recursive partitioning, the presence of distant metastasis was the most powerful predictor of DSS. For M0 patients, age was the next most powerful predictor, with a cutoff of 56 years. For M1 patients, a cutoff at 54 years was most predictive. Having reviewed the analysis, age 55 years was selected as a more robust age cutoff than 45 years. The 10-year DSS by new stage (using age 55 years as the cutoff) was 99.2, 98, 100, and 74 % for stages I-IV, respectively.

CONCLUSION: A change in age cutoff in the AJCC/UICC staging for WDTC to 55 years would improve the accuracy of the system and appropriately prevent low-risk patients being overstaged and overtreated.