title: Defining a Valid Age Cutoff in Staging of Well-Differentiated Thyroid Cancer.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Head and Neck Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, 10021, USA. iainjnixon@gmail.com.
authors.forename: Iain J
authors.initials: IJ
authors.lastname: Nixon
authors.affiliation: Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, USA. kukd@mskcc.org.
authors.forename: Deborah
authors.initials: D
authors.lastname: Kuk
authors.affiliation: Head and Neck Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, 10021, USA. vwreesmann@yahoo.com.
authors.forename: Volkert
authors.initials: V
authors.lastname: Wreesmann
authors.affiliation: Head and Neck Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, 10021, USA. morrisl@mskcc.org.
authors.forename: Luc
authors.initials: L
authors.lastname: Morris
authors.affiliation: Head and Neck Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, 10021, USA. fpalmer2@gmail.com.
authors.forename: Frank L
authors.initials: FL
authors.lastname: Palmer
authors.affiliation: Head and Neck Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, 10021, USA. ganlyi@mskcc.org.
authors.forename: Ian
authors.initials: I
authors.lastname: Ganly
authors.affiliation: Head and Neck Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, 10021, USA. patels@mskcc.org.
authors.forename: Snehal G
authors.initials: SG
authors.lastname: Patel
authors.affiliation: Head and Neck Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, 10021, USA. singhb@mskcc.org.
authors.forename: Bhuvanesh
authors.initials: B
authors.lastname: Singh
authors.affiliation: Department of Endocrinology, Memorial Sloan Kettering Cancer Center, New York, NY, USA. tuttlem@mskcc.org.
authors.forename: R Michael
authors.initials: RM
authors.lastname: Tuttle
authors.affiliation: Head and Neck Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, 10021, USA. Shahaa@mskcc.org.
authors.forename: Ashok R
authors.initials: AR
authors.lastname: Shaha
authors.affiliation: Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, USA. gonenm@mskcc.org.
authors.forename: Mithat
authors.initials: M
authors.lastname: Gönen
authors.affiliation: Head and Neck Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, 10021, USA. shahj@mskcc.org.
authors.forename: Jatin P
authors.initials: JP
authors.lastname: Shah
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology* / Q000601:surgery; D018263:Adenocarcinoma, Follicular / Q000473:pathology* / Q000601:surgery; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002291:Carcinoma, Papillary / Q000473:pathology* / Q000601:surgery; D002454:Cell Differentiation; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D013964:Thyroid Neoplasms / Q000473:pathology* / Q000601:surgery; D055815:Young Adult