Long-term outcome following interstitial laser photocoagulation of benign cold thyroid nodules

To evaluate the long-term efficacy of interstitial laser photocoagulation (ILP) in solitary benign thyroid nodules.

A total of 78 euthyroid outpatients (45 participating in randomized trials) with a benign solitary solid and scintigraphically cold thyroid nodule causing local discomfort were assigned to ILP. ILP (using one laser fiber) was performed under continuous ultrasound (US) guidance and with an output power of 1.5-3.5  W. Thyroid nodule volume was assessed by US and thyroid function determined by routine assays, before and during follow-up. Pressure symptoms and cosmetic complaints were evaluated on a visual analogue scale (0-10  cm). Of the total patients, six had thyroid surgery 6 months after ILP and three were lost to follow-up. The median follow-up for the remaining 69 patients was 67 months (range 12-114).

The overall median nodule volume decreased from 8.2  ml (range 2.0-25.9) to 4.1  ml (range 0.6-33.0; P<0.001) at the final evaluation, corresponding to a median reduction of 51% (range: -194 to 95%). This correlated with a significant decrease in pressure as well as cosmetic complaints. After 12--96 months (median 38 months) of ILP, 21 patients (29%) had thyroid surgery because of an unsatisfactory result. All had benign histology. Thyroid function was unaltered throughout and side effects were restricted to mild local pain.

US-guided ILP results in a satisfactory long-term clinical response in the majority of patients with a benign solitary solid cold thyroid nodule. Further large-scale studies should aim at optimizing selection criteria for ILP, preferably in randomized studies.