Table 3.

Differences in ADCmean between patients per reader according to pathological complete response (pCR) of the breast (ypT0/is)

		Reader 1				Reader 2
		pCR	Non-pCR			pCR	Non-pCR
ADC mean × 10−3 mm2/s	N	mean ± SD	mean ± SD	p-value	N	mean ± SD	mean ± SD	p-value
HR-/HER2+
Baseline ADCmean	40	0.86 ± 0.16	0.86 ± 0.22	0.82	42	0.99 ± 0.23	0.95 ± 0.23	0.59
Post NST ADCmean	26	1.50 ± 0.51	1.32 ± 0.53a	0.39	19	1.49 ± 0.51	1.69 ± 0.21a	0.71
∆ADCmean in %	23	77% ± 58%	35% ± 64%a	0.52	17	56% ± 62%	62% ± 32%a	0.95
HR+ /HER2+
Baseline ADCmean	46	0.83 ± 0.26	0.90 ± 0.38a	0.51	47	0.90 ± 0.24	0.87 ± 0.30	0.37
Post NST ADCmean	25	1.65 ± 0.50	1.38 ± 0.44a	0.36	30	1.73 ± 0.31	1.51 ± 0.43	0.23
∆ADCmean in %	19	86% ± 16%	86% ± 22%	0.66	24	84% ± 35%	92% ± 69%	0.57
Total HER2+
Baseline ADCmean	86	0.84 ± 0.21	0.89 ± 0.33	0.88	89	0.95 ± 0.24	0.89 ± 0.28	0.11
Post NST ADCmean	51	1.55 ± 0.51	1.37 ± 0.44	0.22	49	1.62 ± 0.43	1.55 ± 0.39	0.56
∆ADCmean in %	42	89% ± 67%	69% ± 50%	0.33	41	71% ± 51%	84% ± 61%	0.57
Total HER2+,1.5 T
∆ADCmean in %	7	-a	64% ± 54%	-	6	100%a	75% ± 68%a	-
Total HER2+, 3 T
∆ADCmean in %	15	109% ± 72%	61% ± 56%	0.30	8	71% ± 38%	137% ± 95%a	0.64

ADC apparent diffusion coefficient, pCR pathological complete response, SD standard deviation, HER2+  HER2-positive, HR- hormone receptor-negative, HR+  hormone receptor-positive, NST neoadjuvant systemic therapy

^a n ≤ 5

-differences in number of cases between readers show the difference in the ability to draw a ROI on the baseline and/or post-NST scan