title: Can the follow-up of patients with papillary thyroid carcinoma of low and intermediate risk and excellent response to initial therapy be simplified using second-generation thyroglobulin assays?
abstract: OBJECTIVE
  In view of the low probability of recurrence, the cost-effective follow-up of patients with papillary thyroid carcinoma (PTC) of low or intermediate risk and excellent response to initial therapy represents a challenge. This study evaluated the cases of structural recurrence among these patients.
  
  
  METHODS
  The sample comprised 578 patients with PTC of low or intermediate risk, who were submitted to total thyroidectomy with or without (131) I therapy and exhibited an excellent response to initial therapy defined based on nonstimulated thyroglobulin (Tg) ≤0·2 ng/ml and negative neck ultrasonography (US).
  
  
  RESULTS
  Twelve patients (2%) showed structural recurrence. At the time when recurrence was 'confirmed', Tg elevation had not occurred in only two patients, one with lymph node metastases <1 cm detected by US and the other with pulmonary metastases. Antithyroglobulin antibodies (TgAb) were undetectable in both patients. The first alteration observed in patients with recurrence was Tg elevation in six patients, Tg elevation associated with suspicious US in three, and suspicious US in two. An increase in TgAb was not the first alteration in any of the patients. Among the 560 patients who continued to have Tg ≤ 0·2 ng/ml, US permitted the detection of only one neck recurrence. Measurement of TgAb did not detect any recurrence.
  
  
  CONCLUSIONS
  Our results confirm that in patients with PTC of low or intermediate risk an excellent response to initial therapy can be defined based on nonstimulated Tg ≤ 0·2 ng/ml. Follow-up consisting only of clinical examination and periodic measurement of Tg with a second-generation assay may be sufficient.
authors.affiliation: Santa Casa de Belo Horizonte, Minas Gerais, Brazil. pedrowsrosario@gmail.com.
authors.forename: Pedro Weslley
authors.initials: PW
authors.lastname: Rosario
authors.affiliation: Santa Casa de Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Gabriela Franco
authors.initials: GF
authors.lastname: Mourão
authors.affiliation: Santa Casa de Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Maria Regina
authors.initials: MR
authors.lastname: Calsolari
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000175:diagnosis* / Q000628:therapy; D002291:Carcinoma, Papillary; D003952:Diagnostic Imaging; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012189:Retrospective Studies; D018570:Risk Assessment; D013954:Thyroglobulin / Q000097:blood*; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000628:therapy; D013965:Thyroidectomy; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D013954:Thyroglobulin