title: Long-term follow-up of patients with differentiated thyroid cancer who had negative 131I whole-body scan at first evaluation after treatment.
abstract: OBJECTIVE
  The evaluation of patients with differentiated thyroid cancer is commonly based on serum thyroglobulin (Tg) measurement and 131I whole-body scan (WBS). The first follow-up (6-12 months after initial treatment) shows the response to therapy, a prognostic factor.The aims of the study were to describe the clinical outcome during a long-term follow-up of patients with negative 131I WBS in the first evaluation, and to assess clinical and histological characteristics related to the outcome in this patient population.
  
  
  METHODS
  This retrospective study reviewed data from 209 patients followed at 2 Brazilian hospitals. A minimum of 10 years of follow-up was required.
  
  
  RESULTS
  During mean follow-up of 13.7 ± 4.2 years, 20% of patients developed recurrence. At the end of follow-up, 21% of patients had persistent disease. The clinical and histological characteristics related to adverse outcomes (recurrence or persistent disease) were lymph node metastases at diagnosis, high risk according to American Thyroid Association (ATA) classification, and incomplete response to treatment. Stimulated Tg levels (under thyroid hormone withdrawal) and basal Tg levels (with thyroid hormone) greater than 10 ng/mL at first evaluation were associated with an adverse outcome.
  
  
  CONCLUSIONS
  Negative WBS at first evaluation should not be used as an isolated prognostic factor. This must be considered together with histopathological (ATA classification, lymph node metastases) and clinical/laboratory characteristics (stimulated and basal Tg; response to therapy).
authors.affiliation: From the *Endocrinology Service, Universidade Federal do Rio de Janeiro, Rio de Janeiro; and †Endocrinology Service, Instituto Nacional do Câncer, Rio de Janeiro, Brazil.
authors.forename: Luciana Souza Cruz
authors.initials: LS
authors.lastname: Caminha
authors.forename: Denise Prado
authors.initials: DP
authors.lastname: Momesso
authors.forename: Fernanda
authors.initials: F
authors.lastname: Vaisman
authors.forename: Rossana
authors.initials: R
authors.lastname: Corbo
authors.forename: Mario
authors.initials: M
authors.lastname: Vaisman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002454:Cell Differentiation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D013954:Thyroglobulin / Q000378:metabolism; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy*; D013997:Time Factors; D016896:Treatment Outcome; D051598:Whole Body Imaging; D055815:Young Adult
chemical_list: D007457:Iodine Radioisotopes; D013954:Thyroglobulin