title: Spontaneous remission in thyroid cancer patients after biochemical incomplete response to initial therapy.
abstract: OBJECTIVE
  To validate the American Thyroid Association (ATA) initial risk of recurrence scheme and the Memorial Sloan Kettering Cancer Center (MSKCC) response to therapy re-stratification approach in a large cohort of patients with differentiated thyroid cancer (DTC) treated outside of the United States.
  
  
  METHODS
  Retrospective chart review.
  
  
  METHODS
  Five hundred and six patients with DTC followed for a median of 10 years after total thyroidectomy and RAI remnant ablation at a major cancer centre in Brazil.
  
  
  METHODS
  Final clinical outcomes were assessed based on American Joint Cancer Committee (AJCC)/Union Internationale Contre le Cancer (UICC) staging, ATA risk stratification and response to therapy assessment (excellent, acceptable, biochemical incomplete and structural incomplete).
  
  
  RESULTS
  The AJCC/UICC staging system did not adequately stratify patients with regard to the risk of recurrence/persistent disease. However, the ATA system demonstrated a 13% risk of recurrent/persistent disease in low-risk patients, 36% in intermediate risk patients, and 68% in high-risk patients. Furthermore, an excellent response to therapy decreased the risk of recurrent/persistent disease to 1·4%. At the time of final follow-up, 34% of the biochemical incomplete response patients had been re-classified as having no evidence of disease (NED) without having received any additional therapy beyond continue levothyroxine suppression. Conversely, even after additional therapies, only 9% of the patients with an incomplete structural response were eventually re-classified as NED.
  
  
  CONCLUSIONS
  These data validate the ATA risk classification as an excellent initial predictor of recurrent/persistent disease and confirm the clinical utility of the MSKCC dynamic risk assessment system in a cohort of patients evaluated and treated outside the United States.
authors.affiliation: Endocrinology Service, Universidade Federal do Rio de Janeiro, Brazil.
authors.forename: Fernanda
authors.initials: F
authors.lastname: Vaisman
authors.forename: Denise
authors.initials: D
authors.lastname: Momesso
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Bulzico
authors.forename: Cencita H C N
authors.initials: CH
authors.lastname: Pessoa
authors.forename: Fernando
authors.initials: F
authors.lastname: Dias
authors.forename: Rossana
authors.initials: R
authors.lastname: Corbo
authors.forename: Mário
authors.initials: M
authors.lastname: Vaisman
authors.forename: R Michael
authors.initials: RM
authors.lastname: Tuttle
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis / Q000097:blood; D002277:Carcinoma / Q000097:blood / Q000473:pathology / Q000628:therapy*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging / Q000379:methods; D012075:Remission, Spontaneous; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012955:Societies, Medical; D013964:Thyroid Neoplasms / Q000097:blood / Q000473:pathology / Q000628:therapy*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor