MONTREAL – In the treatment of thyroid nodules with radiofrequency ablation (RFA), the amount of energy delivered per unit volume of the nodule strongly correlates with the extent of nodule volume reduction after 6 and 12 months, suggesting an important indicator of treatment success.
The findings “provide an objective measure or goal energy input to achieve during the [RFA] procedure rather than relying only on the subjective judgment of sonographic changes, and in turn, produce more reliable outcomes for our patients,” first author Samantha A. Wolfe, MD, said in an interview.
Dr. Wolfe, of the department of otolaryngology – head and neck surgery at Johns Hopkins University, Baltimore, presented the findings at the American Thyroid Association annual meeting.
Commenting on the study, Insoo Suh, MD, an associate professor and associate vice chair of Surgical Innovation at New York University Langone Health, agreed that “an accounting of the total amount of energy delivered can be a useful additional data point for the operator when they are determining whether an ablation is successful.”
He noted, however, that the location of a nodule can be an important factor when deciding upon amounts of RF energy.
“Some target areas are too close for comfort to critical structures, such as the trachea or the recurrent laryngeal nerve, so sound judgment would dictate that the energy be dialed down in those areas, even if the price you pay is a slightly lower volume reduction,” he explained.
Analysis of patients given RFA at Johns Hopkins
RFA utilizes RF energy for the reduction of nodule compression and aesthetic symptoms, avoiding the need for thyroid hormone replacement or surgery.
And while decisions regarding RFA treatment location and duration are commonly guided by the operator’s judgment of sonographic changes, those assessments can potentially result in inconsistent outcomes.
In observing a relationship between higher amounts of RF energy and nodule volume reduction, Dr. Wolfe and associates conducted their prospective study of nodules treated by two experienced endocrine surgeons at Johns Hopkins between June 2019 and May 2022 at 6 and 12 months in relation to the amount of total energy delivered during the treatment.
The analysis included 101 nodules, which had a median initial volume of 12.9 mL.
After 6 months, the median volume reduction ratio was 60%, and at 12 months, the median reduction was 64%.
In terms of the goal of achieving 50% or more volume reduction at 6 months, the median energy delivered was significantly higher for nodules that did reach that goal compared with those that had a volume reduction of less than 50% (2,317 vs. 1,912 J/mL, respectively; P = .01).
The figures were similar at 12 months (2,031 vs. 1254 J/mL; P < .01).
In a logistic regression analysis, the amount of energy delivered strongly increased the odds of obtaining a volume reduction ratio of at least 50% (odds ratio, 2.58; P = .048).
“Every twofold increase in energy delivered increases the odds of achieving a 50% volume ratio reduction by 2.58 times,” Dr. Wolfe explained.
Likewise, the same twofold increase in energy delivered also increased the odds of achieving a greater than 80% volume ratio reduction by 2.55 times (OR, 2.55; P = .038), she added.