Learning Curve of USgHIFU Ablation for Uterine Fibroids: A Multi-Center Prospective Study

To verify the stability of high-intensity focused ultrasound (HIFU) technology and the feasibility of training programs with learning curve cumulative summation (LC-CUSUM).

A total of 12 physicians and 720 cases were equally assigned to the learning group and the control group, with 6 physicians and 360 cases per group. The learning group was treated by physicians without HIFU experience and the control group was treated by experienced physicians. Nonperfused volume (NPV) ratio was assessed by contrast-enhanced magnetic resonance imaging. Technical failure was defined as NPV ratio of uterine fibroids <70% and/or major complication, while <80% was set as a stricter standard of training qualification. LC-CUSUM was used to analyze the learning curve.

Physicians with or without HIFU experience in both groups achieved matchable NPV ratios, where a NPV ratio of 92.52% (16.06) was achieved by experienced physicians and 93.82% (16.95) by inexperienced physicians. No major complication was observed. The results of LC-CUSUM analysis showed that, with the standards of the NPV ratio of 70% or 80%, the learning group mastered the technique on the 11th case and the 16th case, respectively, while the control group was stable.

HIFU technology stayed stable in operation, with good safety and sound effectiveness, and was easy to learn. NPV ratio of 70% was considered as an appropriate indicator of training qualification. HIFU has remarkable prospects in achieving a NPV ratio of ≥80% without safety being compromised.