Radiofrequency ablation of benign thyroid nodules: depicting early sign of regrowth by calculating vital volume

Radiofrequency/microwave; thermal ablation; ultrasound; benign thyroid nodule

Objective:

We evaluated long-term follow-up results of radiofrequency ablation of benign thyroid nodules

to analyse the role of marginal vital tissue on nodule regrowth.

Materials and methods:

We reviewed the medical records of 54 patients who underwent radiofrequency

ablation between June 2008 and November 2013 with pressure symptoms, and/or cosmetic

problems. All patients were followed up at least 12months on three occasions. To evaluate an early

sign of regrowth, three types of nodule volumes (total volume, ablated volume and vital volume) were

measured and calculated using ultrasonography. Regrowth was defined as a more than a 50% increase

in the total volume and vital volume increase was defined as a more than 50% increase compared to

the previously reported smallest volume on ultrasonography.

Results:

The mean follow-up period was 39.4 ± 21.7 (range, 13–87) months. Vital volume increases

occurred in 31 nodules (57.4%) and there was regrowth in 13 nodules (24.1%). The mean timing of the

vital volume increase was 27.5 ± 18.5months, and for regrowth it was 39.9 ± 17.5 months. Vital volume

increase tended to precede regrowth.

Conclusion:

Vital volume increase tended to occur earlier than regrowth and might be an early sign of

regrowth in following-up after the radiofrequency ablation of benign thyroid nodules.