Miriam E. Tucker

May 08, 2013

PHOENIX — Ultrasound-guided radiofrequency ablation (RFA) delivered better and faster results than did laser ablation (LA) in patients with large benign thyroid nodules, a randomized study has found.

The results, the first head-to-head comparison of LA with RFA in large nodules, were presented on May 5 by Roberto Valcavi, MD, director of the endocrine unit and thyroid diseases center, Santa Maria Nuova Hospital, Reggio Emilia, Italy, in a late-breaker session at the American Association of Clinical Endocrinologists (AACE) 2013 Scientific & Clinical Congress.

Dr. Valcavi told Medscape Medical News that the current practice for large benign thyroid nodules is open surgery, and at present laser and radiofrequency are the only thermal-ablation techniques available. "The future impact of ultrasound-assisted thermal-ablation techniques should be a reduction of open surgeries," he said.

This study showed several distinct advantages of RFA — the most important the absence of the characteristic charring (carbonization) seen nearly universally with laser-ablation procedures as a result of overheating, he noted.

Session moderator Daniel Duick, MD, a past AACE president now in private practice in Phoenix, Arizona, told Medscape Medical News, "It's a tremendous advance. The difference between laser and a cool-tip radiofrequency is that we don't burn tissue. We don't have to vent tissue. We don't have to smell like the kitchen is on fire."

RFA: Faster, Cleaner, and Cheaper Than LA

Another distinct advantage of RFA is that it can be accomplished in a single session, whereas LA often requires multiple procedures with large nodules. In this study, however, both techniques were performed in single sessions, Dr. Valcavi noted.

The trial randomized 108 consecutive outpatients with symptomatic, cytologically benign large (> 30 mL) thyroid nodules to either ultrasound-guided LA (54 patients, mean age, 51 years) or ultrasound-guided RFA (54 patients, mean age, 47 years). At baseline, nodule volumes were 39.3 mL in the LA group and 40.4 mL for the RFA patients, not significantly different.

Mean total energy delivered was 9624 J for LA vs 60,122 J with RFA. Carbonization, seen as a hyperechoic irreversible mark on ultrasound, occurred in all of the LA patients and none of the RFA patients.

"RFA permitted the delivery of greater energy to obtain larger ablations without carbonization," Dr. Valcavi observed.

At 1 month following the procedure, nodule volumes had dropped to 31.9 mL with LA vs 28.9 mL with RFA (P < .03 for the difference between the 2 procedures). By 3 months, the difference was 27.8 mL vs 26.6 mL (P < .04), and by 6 months, volumes had dropped even further, to 22.6 mL vs 16.9 mL (P < .01).

"We had a faster and greater effect with RFA, of about 70% at 6 months vs 50% with laser," Dr. Valcavi noted.

At 6 months, compressive symptoms as rated on the visual analog scale had been reduced from 5.1 to 2.5 with LA, compared with 5.3 to 0.8 with RFA (P < .01). Levels of thyroid-stimulating hormone and thyroid hormone were unaffected by the procedure in either group.

"Volume reduction of large benign thyroid nodules was greater, faster, and more homogenous after RFA than LA therapy," Dr. Valcavi concluded, adding that reduced cost is yet another RFA advantage: "RFA is a more promising and less expensive thermal-ablation technique than LA."

Results May Aid Expansion of RFA Beyond Radiology

Dr. Duick told Medscape Medical News that the primary use of RFA in the United States has been by interventional radiologists to treat liver tumors and nodules in other tissues.

It is used to treat thyroid nodules too, thus far only through radiological facilities, however, he added.

Of course, data such as these could advance the field. "When you look at efficacy, it's very self-evident… It's a very important procedure," Dr. Duick said.

Neither Dr. Valcavi nor Dr. Duick has reported any relevant financial relationships.

American Association of Clinical Endocrinologists 2013 Scientific & Clinical Congress. Abstract 1100, presented May 5, 2013.

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