title: Follow-up regimen of differentiated thyroid carcinoma in thyroidectomized patients after thyroid hormone withdrawal.
abstract: For differentiated, nonmedullary thyroid carcinoma, postsurgical ablation of thyroid remnants and treatment of residual tumor and metastases with 131I is a potentially curative therapy. The aim of this study was to optimize the diagnostic protocol for the follow-up of thyroidectomized patients.
  
  
  METHODS
  Two hundred fifty-four patients (187 females, 67 males; mean age, 45 y; range, 8-83 y) were studied retrospectively for a mean follow-up period of 2.7 y (range, 1-12.5 y). An evaluation study consisted of a low-dose 131I diagnostic procedure under hyperthyroid conditions (thyroid-stimulating hormone > 30 MicroU/mL), 201TI scintigraphy, and measurement of thyroglobulin (Tg) under hypothyroid conditions. A total of 254 preablation studies (1 study per patient) and 586 follow-up studies (average number of studies, 2.3 per patient) were evaluated.
  
  
  RESULTS
  Before ablation, low-dose 131I screening was useful to estimate the size of the thyroid remnant. Low Tg levels (<10 pmol/L) indicated the absence of metastases. After ablation, undetectable Tg levels indicated the absence of tumor recurrence. When Tg levels were high (>10 pmol/L), local recurrence or metastases were always observed, providing the basis for additional high-dose 131I therapy. In these patients, 201TI imaging did not provide a significant contribution to patient management. In the case of autoantibodies against Tg, both low-dose 131I screening and 201TI scintigraphy may be advocated to allow an aggressive diagnostic work-up.
  
  
  CONCLUSIONS
  Tg plays a key role in follow-up and in making decisions to treat patients with differentiated thyroid carcinoma. The role of 201TI imaging is very limited. In patients with negative low-dose 131I screening, 201TI scintigraphy can be considered when Tg is elevated or cannot be evaluated because of autoantibodies against Tg. Under such circumstances, administration of a therapeutic 131I dose without 201TI imaging can be considered.
authors.affiliation: Department of Nuclear Medicine, University Hospital Nijmegen, The Netherlands.
authors.forename: W J
authors.initials: WJ
authors.lastname: Oyen
authors.forename: C
authors.initials: C
authors.lastname: Verhagen
authors.forename: E
authors.initials: E
authors.lastname: Saris
authors.forename: W J
authors.initials: WJ
authors.lastname: van den Broek
authors.forename: G F
authors.initials: GF
authors.lastname: Pieters
authors.forename: F H
authors.initials: FH
authors.lastname: Corsten
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000097:blood / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D002291:Carcinoma, Papillary / Q000097:blood / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D013794:Thallium Radioisotopes; D013954:Thyroglobulin / Q000097:blood; D013964:Thyroid Neoplasms / Q000097:blood / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D013965:Thyroidectomy
chemical_list: D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D013794:Thallium Radioisotopes; D013954:Thyroglobulin