Information may help to decide who needs multiple ablations
Of note, the effect was stronger with smaller nodules. Those with an initial volume of less than 20 mL had a significantly greater volume ratio reduction than nodules that were 20 mL or larger (61% vs. 48%, respectively; P = .05).
The initial volume of nodules that did, and did not, achieve a 50% volume ratio reduction at 6 months were 10.9 mL versus 19.1 mL, and the initial volumes of those that did, and did not, have at least a 50% reduction at 12 months were 10.5 mL and 41.5 mL.
“At 6 and 12 months, the successfully treated nodules had a significantly smaller immediate initial volume than those that did not,” Dr. Wolfe said.
“This information may aid in identifying patients with large nodules that are less likely to achieve a greater than 50% volume reduction ratio and may require multiple treatments,” she added.
Other factors – including the probe tip size and total energy delivered – did not significantly correlate with volume ratio reduction at 6 or 12 months.
There was also no significant difference in terms of thyroid-stimulating hormone levels among nodules that achieved at least a 50% volume reduction and those that did not.
Nodules that did not have a satisfactory volume reduction at 12 months had a relatively large median total energy value delivered during ablation (103,463 J, compared with 25,969 J among those achieving more than 50% volume ratio reduction), which Dr. Wolfe said likely reflects that those nodules had a large initial volume.
“This speaks to the importance of describing the energy utilized per unit of nodule volume rather than just a gross measurement,” she said during her presentation.
Dr. Wolfe added that in terms of strategies for getting more energy into the nodule, a key approach is time.
“Sometimes you will see sonographic changes very quickly in the nodule, and it could be tempting to consider that area ablated and move on if you only rely on sonographic changes,” she said in an interview. “However, our research shows that, by spending more time, and thus inputting more energy into the nodule, we had better volume reduction.”
Dr. Wolfe and Dr. Suh reported no relevant financial relationships.
A version of this article first appeared on Medscape.com.