Gl. Larosa et al., LEVOTHYROXINE AND POTASSIUM-IODIDE ARE BOTH EFFECTIVE IN TREATING BENIGN SOLITARY SOLID COLD NODULES OF THE THYROID, Annals of internal medicine, 122(1), 1995, pp. 1-8
Objective: To determine the effectiveness of levothyroxine and potassi
um iodide in treating patients with benign solitary cold thyroid nodul
es. Design: Randomized controlled study. Setting: Outpatient clinic at
a university hospital. Patients: 80 patients with solitary solid cold
thyroid nodules found to be benign at cytologic examination were rand
omly assigned to no treatment, suppressive levothyroxine (thyroid-stim
ulating 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 give
n levothyroxine and were followed for a second year. Measurements: Nod
ule volume was measured by ultrasonography at 4-month intervals by an
observer masked to treatment assignment. Results: Mean nodule volume d
ecreased by 40% of the basal volume in the 23 patients receiving levot
hyroxine (P < 0.001) and by 23% of the basat 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 (greater than or equal to 50%) was observed in 9 of
23 patients treated with levothyroxine, in 5 of 25 patients treated wi
th potassium iodide, and in none of 22 untreated patients (P = 0.004).
Only nodules with a volume of 10 mt or less were reduced; nodules wit
h Volumes of 5 mL or less shrank most frequently. Nodule Volume did no
t 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 a
nd, to a lesser extent, potassium iodide are effective in arresting th
e growth or in reducing the volume of benign solitary solid cold thyro
id nodules, especially small ones; discontinuation of therapy may resu
lt in resumed nodule growth.