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 (I-131) dose. Methods: ILP was performed under continuous ultrasound-guidance and with an output power of 2.5-3.5 IV. I-131 was given as a single dose based on thyroid volume and a 24-h thyroid I-131 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 I-131 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 I-131 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 I-131 group (P=0.06 between-group). Two patients in the I-131 group developed hypothyroidism but no major side effects were seen. Conclusions: This first randomized study, comparing ILP with standard therapy, demonstrates that ILP I-131, and I-131 therapy approximately halves thyroid nodule volume within 6 months: but in contrast to extranodular thyroid volume is unaffected by ILP and no patient developed hypothyroidism. Using the present design. ILP seems inferior to I-131 therapy in normalization of serum TSH. The potential value of ILP as a non-surgical alternative to I-131 needs further investigation,