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

Abstract

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