title: Current recommendations for levothyroxine treatment of differentiated thyroid cancer patients are not properly implemented in clinical practice.
abstract: BACKGROUND
  Levothyroxine (L-T4) treatment aims to minimize the risk of differentiated thyroid cancer (DTC) recurrence and should be tailored to patient risk stratification and potential morbidity from adverse effects.
  
  
  OBJECTIVE
  To evaluate the effectiveness of current recommendations on L-T4 treatment of DTC patients in clinical practice.
  
  
  METHODS
  We submitted to in-person interviews and revised the charts of 139 low-risk (LR) and 57 not-low-risk (NLR) DTC patients. A second evaluation made 24-60 months after surgery reclassified 131 patients who maintained (thyroglobulin) Tg≤2 ng/dl with no evidence of relapse/recurrence as LR, whereas the remaining 65 cases were considered NLR.
  
  
  RESULTS
  Only 27% LR patients were appropriately controlled; 18% were kept suppressed; 49% maintained serum TSH levels between 0.11-0.4 mU/l; 21% had TSH=2.5- 4.5 mU/l; and 12% TSH>4.5 mU/l. Among the NLR patients, 24 (37%) of the patients presented serum TSH levels above goal, including 13 (20%) patients with TSH>4.5 mU/l. There were 4 NLR elders whose TSH levels were kept between 0.41 and 4.5 for medical reasons; likewise, 28 NLR patients maintained with low but not undetectable serum TSH levels had cardiovascular and/or bone risk factors, but all the remaining 24 NLR patients were not adequately controlled because of poor treatment compliance. On the other hand, 45% of 152 inappropriately controlled patients presented risks for bone fractures, including 33 patients kept with low serum TSH levels without medical indication.
  
  
  CONCLUSIONS
  We concluded that guidelines are not adequately applied and alternative strategies aiming to increase adherence are urgently needed for DTC patients.
authors.affiliation: Laboratory of Cancer Molecular Genetics, Faculty of Medical Sciences, University of Campinas (Unicamp), Campinas, São Paulo, Brazil.
authors.forename: J F
authors.initials: JF
authors.lastname: Martins de Almeida
authors.forename: W
authors.initials: W
authors.lastname: Gonçalves Tsumura
authors.forename: M
authors.initials: M
authors.lastname: Vaisman
authors.forename: L V
authors.initials: LV
authors.lastname: Montalli Assumpção
authors.forename: L S
authors.initials: LS
authors.lastname: Ward
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D002454:Cell Differentiation; D002755:Choice Behavior; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D055118:Medication Adherence / Q000523:psychology*; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy* / Q000378:metabolism / Q000523:psychology; D017410:Practice Guidelines as Topic; D011379:Prognosis; D012307:Risk Factors; D013954:Thyroglobulin / Q000378:metabolism; D013964:Thyroid Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000523:psychology; D013972:Thyrotropin / Q000378:metabolism; D013974:Thyroxine / Q000627:therapeutic use*
chemical_list: D014408:Biomarkers, Tumor; D013972:Thyrotropin; D013954:Thyroglobulin; D013974:Thyroxine