title: Comparable outcomes for patients with pT1a and pT1b differentiated thyroid cancer: Is there a need for change in the AJCC classification system?
abstract: BACKGROUND
  The current American Joint Committee on Cancer TNM classification for differentiated thyroid cancer (DTC) separates T1 status into T1a and T1b based on a 1-cm cutoff for maximal tumor dimension. In 2009, the American Thyroid Association recommended total thyroidectomy for tumors >1 cm in contrast to the possibility of lobectomy for tumors ≤ 1 cm. Our aim was to investigate the prognostic significance of a 1-cm tumor cutoff.
  
  
  METHODS
  From an institutional database of 3,664 patients with DTC, 1,522 patients with T1 tumors without neck disease or distant metastases were identified. Patient, tumor, and treatment characteristics were compared. Disease-specific survival (DSS) and recurrence-free survival (RFS) outcomes were analyzed.
  
  
  RESULTS
  Total thyroidectomy rates were similar between patients with T1a and T1b tumors (P = .307). With a median follow-up of 46 months (range, 1-320), there were no disease-specific deaths in the T1a or T1b groups. In total, 18 patients (1.2%) experienced a recurrence. Five-year RFS was comparable for patients with T1a and T1b tumors (98.6 vs 98.6%; P = .224).
  
  
  CONCLUSIONS
  T1a and T1b tumors have similar prognosis both in terms of DSS and RFS. It seems that a distinction between tumors of <1 and >1 cm is of no prognostic benefit.
authors.affiliation: Department of Surgery, Head and Neck Service, Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Laura Y
authors.initials: LY
authors.lastname: Wang
authors.affiliation: Department of Surgery, Head and Neck Service, Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Iain J
authors.initials: IJ
authors.lastname: Nixon
authors.affiliation: Department of Surgery, Head and Neck Service, Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Frank L
authors.initials: FL
authors.lastname: Palmer
authors.affiliation: Department of Surgery, Head and Neck Service, Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Dorothy
authors.initials: D
authors.lastname: Thomas
authors.affiliation: Department of Medicine, Endocrine Service, Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: R Michael
authors.initials: RM
authors.lastname: Tuttle
authors.affiliation: Department of Surgery, Head and Neck Service, Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Ashok R
authors.initials: AR
authors.lastname: Shaha
authors.affiliation: Department of Surgery, Head and Neck Service, Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Snehal G
authors.initials: SG
authors.lastname: Patel
authors.affiliation: Department of Surgery, Head and Neck Service, Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Jatin P
authors.initials: JP
authors.lastname: Shah
authors.affiliation: Department of Surgery, Head and Neck Service, Memorial Sloan Kettering Cancer Center, New York, NY. Electronic address: ganlyi@mskcc.org.
authors.forename: Ian
authors.initials: I
authors.lastname: Ganly
mesh_terms: D000328:Adult; D026683:Advisory Committees / Q000592:standards*; D000368:Aged; D000369:Aged, 80 and over; D001707:Biopsy, Needle; D016208:Databases, Factual; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D020380:Needs Assessment; D009361:Neoplasm Invasiveness / Q000473:pathology; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate; D013964:Thyroid Neoplasms / Q000145:classification* / Q000401:mortality* / Q000473:pathology / Q000601:surgery*; D013965:Thyroidectomy / Q000379:methods* / Q000401:mortality; D013997:Time Factors; D014481:United States