title: Levothyroxine and potassium iodide are both effective in treating benign solitary solid cold nodules of the thyroid.
abstract: OBJECTIVE
  To determine the effectiveness of levothyroxine and potassium iodide in treating patients with benign solitary cold thyroid nodules.
  
  
  METHODS
  Randomized controlled study.
  
  
  METHODS
  Outpatient clinic at a university hospital.
  
  
  METHODS
  80 patients with solitary solid cold thyroid nodules found to be benign at cytologic examination were randomly assigned to no treatment, suppressive levothyroxine (thyroid-stimulating hormone level, < 0.3 mU/L), or low-dose potassium iodide (2 mg every 2 weeks). Seventy patients completed the 1-year study. After 1 year, patients receiving treatment discontinued drug therapy and were re-evaluated 4 months later; patients receiving no treatment were given levothyroxine and were followed for a second year.
  
  
  METHODS
  Nodule volume was measured by ultrasonography at 4-month intervals by an observer masked to treatment assignment.
  
  
  RESULTS
  Mean nodule volume decreased by 40% of the basal volume in the 23 patients receiving levothyroxine (P < 0.001) and by 23% of the basal volume in the 25 patients receiving potassium iodide (P = 0.053). Volume slightly increased in the 22 untreated patients (P = 0.085). A clinically relevant reduction in nodule volume (> or = 50%) was observed in 9 of 23 patients treated with levothyroxine, in 5 of 25 patients treated with potassium iodide, and in none of 22 untreated patients (P = 0.004). Only nodules with a volume of 10 mL or less were reduced; nodules with volumes of 5 mL or less shrank most frequently. Nodule volume did not relevantly increase in treated patients but did increase in 3 of the 22 untreated patients. Drug withdrawal resulted in an increased mean nodule volume (P = 0.004) after 4 months.
  
  
  CONCLUSIONS
  Levothyroxine and, to a lesser extent, potassium iodide are effective in arresting the growth or in reducing the volume of benign solitary solid cold thyroid nodules, especially small ones; discontinuation of therapy may result in resumed nodule growth.
authors.affiliation: University of Catania, Italy.
authors.forename: G L
authors.initials: GL
authors.lastname: La Rosa
authors.forename: L
authors.initials: L
authors.lastname: Lupo
authors.forename: D
authors.initials: D
authors.lastname: Giuffrida
authors.forename: D
authors.initials: D
authors.lastname: Gullo
authors.forename: R
authors.initials: R
authors.lastname: Vigneri
authors.forename: A
authors.initials: A
authors.lastname: Belfiore
mesh_terms: D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011193:Potassium Iodide / Q000627:therapeutic use*; D016606:Thyroid Nodule / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000473:pathology; D013974:Thyroxine / Q000627:therapeutic use*; D014463:Ultrasonography
chemical_list: D011193:Potassium Iodide; D013974:Thyroxine