title: An International Multi-Institutional Validation of Age 55 Years as a Cutoff for Risk Stratification in the AJCC/UICC Staging System for Well-Differentiated Thyroid Cancer.
abstract: BACKGROUND
  Age is a critical factor in outcome for patients with well-differentiated thyroid cancer. Currently, age 45 years is used as a cutoff in staging, although there is increasing evidence to suggest this may be too low. The aim of this study was to assess the potential for changing the cut point for the American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) staging system from 45 years to 55 years based on a combined international patient cohort supplied by individual institutions.
  
  
  METHODS
  A total of 9484 patients were included from 10 institutions. Tumor (T), nodes (N), and metastasis (M) data and age were provided for each patient. The group was stratified by AJCC/UICC stage using age 45 years and age 55 years as cutoffs. The Kaplan-Meier method was used to calculate outcomes for disease-specific survival (DSS). Concordance probability estimates (CPE) were calculated to compare the degree of concordance for each model.
  
  
  RESULTS
  Using age 45 years as a cutoff, 10-year DSS rates for stage I-IV were 99.7%, 97.3%, 96.6%, and 76.3%, respectively. Using age 55 years as a cutoff, 10-year DSS rates for stage I-IV were 99.5%, 94.7%, 94.1%, and 67.6%, respectively. The change resulted in 12% of patients being downstaged, and the downstaged group had a 10-year DSS of 97.6%. The change resulted in an increase in CPE from 0.90 to 0.92.
  
  
  CONCLUSIONS
  A change in the cutoff age in the current AJCC/UICC staging system from 45 years to 55 years would lead to a downstaging of 12% of patients, and would improve the statistical validity of the model. Such a change would be clinically relevant for thousands of patients worldwide by preventing overstaging of patients with low-risk disease while providing a more realistic estimate of prognosis for those who remain high risk.
authors.affiliation: 1 Department of Surgery/Endocrinology, Memorial Sloan Kettering Cancer Center , New York, New York.
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authors.initials: IJ
authors.lastname: Nixon
authors.affiliation: 1 Department of Surgery/Endocrinology, Memorial Sloan Kettering Cancer Center , New York, New York.
authors.forename: Laura Y
authors.initials: LY
authors.lastname: Wang
authors.affiliation: 1 Department of Surgery/Endocrinology, Memorial Sloan Kettering Cancer Center , New York, New York.
authors.forename: Jocelyn C
authors.initials: JC
authors.lastname: Migliacci
authors.affiliation: 2 Department of Otolaryngology, Mount Sinai Hospital , Toronto, Canada .
authors.forename: Antoine
authors.initials: A
authors.lastname: Eskander
authors.affiliation: 3 Department of Surgery, University of California , Davis Medical Center, Sacramento, California.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Campbell
authors.affiliation: 4 Department of Endocrine Surgery, Endocrine Surgical Unit, University of Sydney , Sydney, Australia .
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authors.lastname: Aniss
authors.affiliation: 5 Department of Endocrine Surgery, MD Anderson , Houston, Texas.
authors.forename: Lilah
authors.initials: L
authors.lastname: Morris
authors.affiliation: 6 Department of Endocrinology, Endocrine Service, Instituto Nacional do Cancer , Rio de Janeiro, Brazil .
authors.forename: Fernanda
authors.initials: F
authors.lastname: Vaisman
authors.affiliation: 6 Department of Endocrinology, Endocrine Service, Instituto Nacional do Cancer , Rio de Janeiro, Brazil .
authors.forename: Rossana
authors.initials: R
authors.lastname: Corbo
authors.affiliation: 7 Department of Endocrinology, Endocrinology Service, Faculdade de Medicina-Universidade Federal do Rio de Janeiro , Rio de Janeiro, Brazil .
authors.forename: Denise
authors.initials: D
authors.lastname: Momesso
authors.affiliation: 7 Department of Endocrinology, Endocrinology Service, Faculdade de Medicina-Universidade Federal do Rio de Janeiro , Rio de Janeiro, Brazil .
authors.forename: Mario
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authors.lastname: Vaisman
authors.affiliation: 8 Department of Head and Neck Surgery, Barretos Cancer Hospital , Barretos, Brazil .
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authors.affiliation: 4 Department of Endocrine Surgery, Endocrine Surgical Unit, University of Sydney , Sydney, Australia .
authors.forename: Diana
authors.initials: D
authors.lastname: Learoyd
authors.affiliation: 9 Department of Surgery, Head and Neck Surgical Oncology and Nuclear Medicine, Cancer Care Manitoba and University of Manitoba , Winnipeg, Canada .
authors.forename: William D
authors.initials: WD
authors.lastname: Leslie
authors.affiliation: 9 Department of Surgery, Head and Neck Surgical Oncology and Nuclear Medicine, Cancer Care Manitoba and University of Manitoba , Winnipeg, Canada .
authors.forename: Richard W
authors.initials: RW
authors.lastname: Nason
authors.affiliation: 1 Department of Surgery/Endocrinology, Memorial Sloan Kettering Cancer Center , New York, New York.
authors.forename: Deborah
authors.initials: D
authors.lastname: Kuk
authors.affiliation: 1 Department of Surgery/Endocrinology, Memorial Sloan Kettering Cancer Center , New York, New York.
authors.forename: Volkert
authors.initials: V
authors.lastname: Wreesmann
authors.affiliation: 1 Department of Surgery/Endocrinology, Memorial Sloan Kettering Cancer Center , New York, New York.
authors.forename: Luc
authors.initials: L
authors.lastname: Morris
authors.affiliation: 1 Department of Surgery/Endocrinology, Memorial Sloan Kettering Cancer Center , New York, New York.
authors.forename: Frank L
authors.initials: FL
authors.lastname: Palmer
authors.affiliation: 1 Department of Surgery/Endocrinology, Memorial Sloan Kettering Cancer Center , New York, New York.
authors.forename: Ian
authors.initials: I
authors.lastname: Ganly
authors.affiliation: 1 Department of Surgery/Endocrinology, Memorial Sloan Kettering Cancer Center , New York, New York.
authors.forename: Snehal G
authors.initials: SG
authors.lastname: Patel
authors.affiliation: 1 Department of Surgery/Endocrinology, Memorial Sloan Kettering Cancer Center , New York, New York.
authors.forename: Bhuvanesh
authors.initials: B
authors.lastname: Singh
authors.affiliation: 1 Department of Surgery/Endocrinology, Memorial Sloan Kettering Cancer Center , New York, New York.
authors.forename: R Michael
authors.initials: RM
authors.lastname: Tuttle
authors.affiliation: 1 Department of Surgery/Endocrinology, Memorial Sloan Kettering Cancer Center , New York, New York.
authors.forename: Ashok R
authors.initials: AR
authors.lastname: Shaha
authors.affiliation: 1 Department of Surgery/Endocrinology, Memorial Sloan Kettering Cancer Center , New York, New York.
authors.forename: Mithat
authors.initials: M
authors.lastname: Gönen
authors.affiliation: 9 Department of Surgery, Head and Neck Surgical Oncology and Nuclear Medicine, Cancer Care Manitoba and University of Manitoba , Winnipeg, Canada .
authors.forename: K Alok
authors.initials: KA
authors.lastname: Pathak
authors.affiliation: 10 Department of Endocrine Surgery, University of California , San Francisco, San Francisco, California.
authors.forename: Wen T
authors.initials: WT
authors.lastname: Shen
authors.affiliation: 4 Department of Endocrine Surgery, Endocrine Surgical Unit, University of Sydney , Sydney, Australia .
authors.forename: Mark
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authors.lastname: Sywak
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authors.lastname: Kowalski
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authors.forename: Jeremy
authors.initials: J
authors.lastname: Freeman
authors.affiliation: 5 Department of Endocrine Surgery, MD Anderson , Houston, Texas.
authors.forename: Nancy
authors.initials: N
authors.lastname: Perrier
authors.affiliation: 1 Department of Surgery/Endocrinology, Memorial Sloan Kettering Cancer Center , New York, New York.
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authors.initials: JP
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mesh_terms: D000367:Age Factors; D001938:Brazil; D002454:Cell Differentiation; D003661:Decision Support Techniques; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D009517:New South Wales; D009656:North America; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013964:Thyroid Neoplasms / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D016896:Treatment Outcome