Evaluating the learning curve of high intensity focus ultrasound for breast fibroadenoma by CUSUM analysis: a multi-center study

Figures & data

Figure 1. The significant scale changes during HIFU treatment for breast fibroadenoma. A: Pre-HIFU ultrasound showed a hypoechoic breast fibroadenoma. B: Intra-HIFU ultrasound showed a significant hyperechoic scale changes emerging during HIFU (white arrow). C: Post-HIFU ultrasound showed that the significant hyperechoic scale change covered the whole fibroadenoma.

Figure 2. The trend of the treatment time and CUSUM in the two centers. A: The trend of the treatment time in HIFU treatment of breast fibroadenoma in Center 1. B: The learning curve (CUSUM chart) of HIFU treatment time in Center 1 (60 was the vertex of the curve). C: The trend of the treatment time in HIFU treatment of breast fibroadenoma in Center 2. D: The learning curve (CUSUM chart) of HIFU treatment time in Center 2 (65 was the vertex of the curve).

Table 1. Baseline characteristics of patients in two centers.

	Center 1			Center 2
Variables	Initial phase (n = 34)	Consolidation phase (n = 23)	p Value	Initial phase (n = 15)	Consolidation phase (n = 38)	p Value
Age (y)	27.00 (23.75, 33.00)	24.00 (21.00, 28.00)	0.072	25.00 (21.00, 32.00)	32.50 (23.75, 41.00)	0.097
BMI (kg/m^2)	20.87 (19.53, 22.38)	19.81 (18.75, 20.58)	0.051	19.83 (18.99, 21.10)	21.54 (19.41, 23.61)	0.057

Table 2. Baseline characteristics of lesions in two centers.

	Center 1			Center 2
Variables	Initial phase (n = 60)	Consolidation phase (n = 38)	p Value	Initial phase (n = 65)	Consolidation phase (n = 92)	p Value
Fibroadenoma diameter (mm)	15.20 (11.40, 19.95)	15.55 (13.00, 20.20)	0.535	15.00 (11.00, 22.20)	14.95 (10.10, 20.88)	0.535
Volume (mm^3)	758.35 (273.65, 1507.10)	820.99 (405.99, 2188.02)	0.563	706.46 (330.51, 2187.99)	781.98 (233.08, 1831.09)	0.563
Distance from shallow margin of fibroadenoma to skin (mm)	14.60 ± 5.82	10.52 ± 6.68	0.107	11.70 (6.85, 15.00)	9.45 (5.40, 16.28)	0.349
Distance from deep margin of fibroadenoma to the pectoralis major (mm)	1.10 (0.00, 4.88)	4.50 (1.33, 7.88)	0.029	5.00 (1.90, 9.00)	5.15 (2.23, 8.45)	0.836

Figure 3. The box plot of screening time, treatment time, sonication time and hyperechoic scale change emerging time between groups in the two centers. A: Screening time. B: Treatment time. C: Sonication time. D: Hyperechoic scale change emerging time. *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001.

Figure 4. The box plot of sonication energy, NPV ratio, EEF and intra-treatment VAS scores between groups in the two centers. A: Sonication energy. B: NPV ratio. C: EEF. D: Intra-treatment VAS scores. *p < 0.05; **p < 0.01.

Table 3. HIFU treatment results for fibroadenoma in two centers.

	Center 1			Center 2
Variables	Initial phase (n = 60)	Consolidation phase (n = 38)	p Value	Initial phase (n = 65)	Consolidation phase (n = 92)	p Value
Screening time (min)	5.00 (2.00, 9.75)	2.00 (1.00, 4.00)	0.000	7.00 (2.50, 14.75)	2.00 (1.00, 4.00)	0.003
Treatment time (min)	9.00 (5.00, 15.75)	7.00 (4.00, 10.25)	0.030	15.00 (6.00, 29.25)	7.50 (5.00, 12.00)	0.000
Sonication time (s)	61.50 (31.25, 111.00)	36.50 (22.00, 59.50)	0.003	73.00 (32.75, 142.25)	43.58 (23.25, 63.75)	0.000
Hyperechoic scale changes emerging time (s)	11.50 (6.00, 24.75)	4.00 (3.00, 8.25)	0.000	13.00 (4.00, 30.00)	7.00 (3.00, 15.75)	0.022
Sonication energy (kJ)	10.37 (5.62, 20.20)	8.35(4.49, 14.75)	0.166	9.30 (4.48, 20.14)	7.80 (3.40, 12.00)	0.037
NPV ratio (%)	95.89 (72.17, 118.46)	89.36 (70.71, 104.25)	0.268	77.33 (52.79, 100)	92.47 (70.02, 110.17)	0.010
EEF (J/mm^3)	18.46 (7.52, 39.77)	12.20 (8.02, 19.65)	0.063	17.48 (8.83, 35.51)	11.03 (6.10, 26.30)	0.022
Intra-treatment VAS scores	5.00 (3.00, 6.00)	3.00 (1.00, 6.00)	0.094	2.00 (1.00, 3.00)	2.00 (1.00, 3.00)	0.813