BACKGROUND
Thyroid nodules are quite common. The concern of any thyroid nodule is whether they are cancerous. Overall, only ~5% of nodules are cancerous, so the vast majority are benign. Even though most are benign, sometimes they cause problems, including neck discomfort from compression or patients do not like their appearance. At present, surgery is the main option for benign nodules causing these problems. However, patients may prefer a non-surgical treatment to get rid of or reduce the size of the nodule if this were available.

Two such non-surgical options are radio-frequency ablation (RFA – like localized microwave energy in a nodule via a needle) or laser ablation (LA – localized laser treatments in a nodule via a needle). These procedures are currently being used more frequently in Europe, but are gaining popularity in the United States.

One downside to these procedures is the possibility of nodule regrowth. This study reviewed the experience of multiple centers in Italy using these techniques and the rates of nodule regrowth and need for repeat treatment after the initial therapy.

THE FULL ARTICLE TITLE
Bernardi S et al 2020 Five-year results of radiofrequency and laser ablation of benign thyroid nodules: A multicenter study from the Italian Minimally Invasive Treatments of the Thyroid Group. Thyroid 30:1759– 1770. PMID: 32578498.

SUMMARY OF THE STUDY
This study evaluated the outcomes of RFA or LA from 8 Italian medical centers for 5 years after initial treatment and tried to determine factors that predicted success in terms of no nodule regrowth or not needing retreatment over that time.

There was a total of 406 patients analyzed (average age 57 and 75% women). Of these, 53% received RFA and 47% received LA. About 94% of the nodules were completely solid or mostly solid with only 5% mostly fluid filled and 1% completely fluid filled. At the end of 5 years after initial treatment, there was an overall 77% reduction in size of the nodules undergoing RFA while LA resulted in an average of 57% reduction in size after 5 years.

In all, 28% of patients (115 patients) had nodule regrowth and 32 of them (28%) required retreatment. The main predictor of regrowth was the amount of energy delivered to the nodule by either technique (the lower the energy, the greater chance of regrowth). Overall, more nodules undergoing LA had regrowth as compared to RFA. A total of 46 patients (11%) ultimately had surgery remove their thyroid. Of the patients that ultimately had surgery for these presumed benign thyroid nodules, 35% had a thyroid cancer discovered. If the initial RFA or LA treatment resulted in < 20% decreased nodule size in the first year, this was more likely to mean the nodule had thyroid cancer in it.

WHAT ARE THE IMPLICATIONS OF THIS STUDY?
RFA and LA are minimally invasive, non-surgical options for decreasing the size of bothersome thyroid nodules. Most nodules do not regrow, though RFA seems to be more effective overall. If the nodule does not shrink by > 20% a year after treatment, one should consider it may contain a thyroid cancer.

This study is important to patients as it shows an overall less invasive technique for shrinking bothersome thyroid nodules and suggests the treatment is likely to be successful with most nodules staying significantly smaller for at least 5 years. These techniques should not be used as primary treatment for known thyroid cancer, but if the nodules do not shrink as much as expected (<20% after the first year), the chance of thyroid cancer being present should be considered.

—Joshua Klopper, MD

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