title: Survival from Differentiated Thyroid Cancer: What Has Age Got to Do with It?
abstract: BACKGROUND
  In most staging systems, 45 years of age is used to differentiate low risk thyroid cancer from high risk thyroid cancer. However, recent studies have questioned both the precise 45 year age point and the concept of using a binary cut off as accurate predictors of disease specific mortality.
  
  
  METHODS
  A cohort of 3664 thyroid cancer patients that received surgery and adjuvant treatment at Memorial Sloan Kettering Cancer Center (MSKCC) from the years 1985 to 2010 were analyzed to determine the significance of age at diagnosis as a categorical variable at a variety of age cutoffs (5 year intervals between 30 and 70 years of age). The unadjusted and adjusted hazard ratio for the association between disease-specific survival and age was determined using a Cox proportional hazards model adjusted for other predictive variables sex, histology, and pathological T, N, and M status. Furthermore, predictive nomograms of disease-specific mortality were created and validated on an external dataset of 4551 patients to evaluate the impact of age at diagnosis as both a categorical and continuous variable.
  
  
  RESULTS
  In the MSKCC cohort, with a median follow-up time of 54 months (range 1-332), there were 59 deaths from thyroid cancer with a 10 year disease-specific survival of 96%. Adjusted hazard ratios for all age cutoffs from age 30 to age 70 years were significant. There was no specific cutoff age which risk stratifies patients with differentiated thyroid cancer (DTC). Categorizing age into five strata (<40, 40-49, 50-59, 60-69 and >70 years) showed a 37-fold increase in hazard ratio from age <40 years to age >70 years. A predictive nomogram using age as a continuous variable with other predictive variables had a high concordance index of 96%. Validation on the external cohort had a concordance index of 73%.
  
  
  CONCLUSIONS
  Mortality from DTC increases progressively with advancing age. There is no specific cutoff age which risk stratifies patients with DTC. A predictive nomogram using age as a continuous variable may be a more appropriate tool for stratifying patients with DTC and for predicting outcome.
authors.affiliation: 1 Department of Surgery, Head and Neck Service, Memorial Sloan Kettering Cancer Center , New York, New York.
authors.forename: Ian
authors.initials: I
authors.lastname: Ganly
authors.affiliation: 1 Department of Surgery, Head and Neck Service, Memorial Sloan Kettering Cancer Center , New York, New York.
authors.forename: Iain J
authors.initials: IJ
authors.lastname: Nixon
authors.affiliation: 1 Department of Surgery, Head and Neck Service, 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, Head and Neck Service, 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, Head and Neck Service, Memorial Sloan Kettering Cancer Center , New York, New York.
authors.forename: Jocelyn C
authors.initials: JC
authors.lastname: Migliacci
authors.affiliation: 2 University of Sydney Endocrine Surgical Unit , Sydney, Australia .
authors.forename: Ahmad
authors.initials: A
authors.lastname: Aniss
authors.affiliation: 2 University of Sydney Endocrine Surgical Unit , Sydney, Australia .
authors.forename: Mark
authors.initials: M
authors.lastname: Sywak
authors.affiliation: 3 Department of Otolaryngology-Head and Neck Surgery, Mount Sinai Hospital , Toronto, Canada .
authors.forename: Antoine E
authors.initials: AE
authors.lastname: Eskander
authors.affiliation: 3 Department of Otolaryngology-Head and Neck Surgery, Mount Sinai Hospital , Toronto, Canada .
authors.forename: Jeremy L
authors.initials: JL
authors.lastname: Freeman
authors.affiliation: 4 Department of Surgery, University of California , Davis Medical Center, Sacramento, California.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Campbell
authors.affiliation: 5 Department of Surgery, University of California , San Francisco, San Francisco, California.
authors.forename: Wen T
authors.initials: WT
authors.lastname: Shen
authors.affiliation: 6 Endocrine Service, Instituto Nacional do Cancer , Rio de Janeiro, Brazil .
authors.forename: Fernanda
authors.initials: F
authors.lastname: Vaisman
authors.affiliation: 7 Endocrine Service, Universidade Federal do Rio de Janeiro , Rio de Janeiro, Brazil .
authors.forename: Denise
authors.initials: D
authors.lastname: Momesso
authors.affiliation: 6 Endocrine Service, Instituto Nacional do Cancer , Rio de Janeiro, Brazil .
authors.forename: Rossana
authors.initials: R
authors.lastname: Corbo
authors.affiliation: 7 Endocrine Service, Universidade Federal do Rio de Janeiro , Rio de Janeiro, Brazil .
authors.forename: Mario
authors.initials: M
authors.lastname: Vaisman
authors.affiliation: 8 Department of Medicine, Endocrinology Service, Memorial Sloan Kettering Cancer Center , New York, New York.
authors.forename: Ashok
authors.initials: A
authors.lastname: Shaha
authors.affiliation: 8 Department of Medicine, Endocrinology Service, 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, Head and Neck Service, Memorial Sloan Kettering Cancer Center , New York, New York.
authors.forename: Jatin P
authors.initials: JP
authors.lastname: Shah
authors.affiliation: 1 Department of Surgery, Head and Neck Service, Memorial Sloan Kettering Cancer Center , New York, New York.
authors.forename: Snehal G
authors.initials: SG
authors.lastname: Patel
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality* / Q000473:pathology; D000328:Adult; D000367:Age Factors; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D049451:Nomograms; D011379:Prognosis; D015996:Survival Rate; D013964:Thyroid Neoplasms / Q000401:mortality* / Q000473:pathology