title: Thyroid dysfunction in laryngectomees-10 years after treatment.
abstract: BACKGROUND
  Hypothyroidism is 1 of the complications that follow treatment of various head and neck cancers. In the literature, reviews using different primary sites and differences in treatment modalities make comparison of post-treatment hypothyroidism not possible. The objective of this study was to evaluate the incidence of hypothyroidism in a homogenous group of patients who were treated with total laryngectomy and irradiation for laryngeal carcinoma and to assess the importance of different variables in the occurrence of hypothyroidism.
  
  
  METHODS
  A retrospective review of 147 total laryngectomy patients between 1993 and 2003 was carried out. Serum thyroxine level and free T4 levels were assessed in all patients. Hypothyroidism was classified as subclinical (increased thyroid-stimulating hormone and normal free T4 levels) and clinical (increased thyroid-stimulating hormone and decreased free T4 levels).
  
  
  RESULTS
  The results showed that the overall incidence of hypothyroidism was 49% (44% subclinical and 5% clinical). Hemithyroidectomy and advanced tumor staging were risk factors for the development of hypothyroidism in these patients (p < .05) with a relative risk of 2.1 (CI 95%, 1.4-3.1) and 1.3 (CI 95%, 1.1-1.6), respectively. During follow-up, 19.9% of patients developed hypothyroidism at 3 years, 38.6% at 6 years; at 10 year follow-up, 93.3% of them had hypothyroidism.
  
  
  CONCLUSIONS
  In conclusion, hypothyroidism is a frequent complication in patients treated with radiotherapy and total laryngectomy for laryngeal cancer, especially when treatment includes hemithyroidectomy. These patients should have their thyroid function evaluated periodically even 10 years after treatment.
authors.affiliation: Division of Otorhinolaryngology Head and Neck Surgery, Department of Surgery, University of Hong Kong Medical Centre, Queen Mary Hospital, Hong Kong.
authors.forename: Ambrose Chung-Wai
authors.initials: AC
authors.lastname: Ho
authors.forename: Wai-Kuen
authors.initials: WK
authors.lastname: Ho
authors.forename: Paul Kin-Yip
authors.initials: PK
authors.lastname: Lam
authors.forename: Anthony Po-Wing
authors.initials: AP
authors.lastname: Yuen
authors.forename: William Ignace
authors.initials: WI
authors.lastname: Wei
mesh_terms: D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use; D017024:Chemotherapy, Adjuvant; D002945:Cisplatin / Q000627:therapeutic use; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007037:Hypothyroidism / Q000453:epidemiology / Q000209:etiology*; D007822:Laryngeal Neoplasms / Q000473:pathology / Q000628:therapy; D007825:Laryngectomy / Q000009:adverse effects*; D008297:Male; D015999:Multivariate Analysis; D018714:Radiotherapy, Adjuvant; D012189:Retrospective Studies; D012307:Risk Factors; D013965:Thyroidectomy / Q000009:adverse effects / Q000379:methods
chemical_list: D000970:Antineoplastic Agents; D002945:Cisplatin