Treatment of uterine fibroid tumors in an in situ rat model using high-intensity focused ultrasound.

OBJECTIVE

To determine the efficacy and safety of high-intensity focused ultrasound (HIFU) for the treatment of uterine fibroid tumors in an in situ animal model.

DESIGN

High-intensity focused ultrasound was applied intraoperatively to uterine fibroid tumors in rats.

SETTING

Department of Bioengineering, and Applied Physics Laboratory, University of Washington, Seattle, Washington.

ANIMAL(S): Thirty-five tumors in 27 Eker rats that had spontaneous in situ uterine fibroids were randomly assigned into two groups receiving HIFU (n = 29) or sham (n = 6) treatments.

INTERVENTION(S): Animals were anesthetized, and tumors were exposed surgically. The HIFU was applied at 3.5 MHz in 10-second bursts to produce coagulative necrosis lesions (3 mm by 10 mm), spaced 5 mm apart. Sham treatments consisted of exposing the tumors, and handling them similarly to those in the HIFU treatment group, but HIFU was not applied.

MAIN OUTCOME MEASURE(S): Tumor volume was measured every week transabdominally using B-mode ultrasound imaging. Gross examination and histological analysis were performed after euthanasia.

RESULT(S): More than half of the tumors in the HIFU treatment group showed significant tumor volume reduction. The average tumor volume in the sham treatment group increased 40-fold. Gross and histological analysis showed coagulative necrosis of tumor cells in the HIFU treatment group.

CONCLUSION(S): The HIFU may provide an effective and safe method of treating uterine fibroid tumors.