Randomized prospective study comparing a single radioiodine dose and a single laser therapy session in autonomously functioning thyroid nodules.

OBJECTIVE

To compare the efficacy of interstitial laser photocoagulation (ILP) with radioiodine in hot thyroid nodules.

DESIGN

Thirty consecutive outpatients with subclinical or mild hyperthyroidism and a scintigraphically solitary hot nodule with extraglandular suppression were randomized to either one ILP session or one radioiodine ((131)I) dose.

METHODS

ILP was performed under continuous ultrasound-guidance and with an output power of 2.5-3.5 W. (131)I was given as a single dose based on thyroid volume and a 24-h thyroid (131)I uptake. Thyroid function and nodule volume were evaluated at inclusion and at 1, 3 and 6 months after treatment.

RESULTS

Normalization of serum TSH was achieved in 7 out of 14 patients in the ILP group and in all 15 patients in the (131)I group (P=0.0025). In the ILP group, mean thyroid nodule volume reduction was 44+/-5% (s.e.m.; P<0.001), and in the (131)I group 47+/-8% (P<0.001), within 6 months, without between-group difference (P=0.73). The mean reduction of total thyroid volume was 7+/-5% in the ILP group (P=0.20) and 26+/-8% (P=0.006) in the (131)I group (P=0.06 between-group). Two patients in the (131)I group developed hypothyroidism but no major side effects were seen.

CONCLUSIONS

This first randomized study, comparing ILP with standard therapy, demonstrates that ILP and (131)I therapy approximately halves thyroid nodule volume within 6 months; but in contrast to (131)I, extranodular thyroid volume is unaffected by ILP and no patient developed hypothyroidism. Using the present design, ILP seems inferior to (131)I therapy in normalization of serum TSH. The potential value of ILP as a non-surgical alternative to (131)I needs further investigation.