Table 2.

Multivariate analysis of HER2, clinicopathological, and treatment variables with IBE as endpoint.

			Univariate		Multivariate
Variable	Subgroup	n	HR (95% CI)	P	HR (95% CI)	P
HER2	Negative	398	1 (reference)	—	1 (reference)	—
	Positive (IHC 3+)	214	2.03 (1.45–2.86)	<0.0001	1.92 (1.33–2.76)	0.0004
Age	Years (mean)	57.4	0.99 (0.96–1.02)	0.42	0.98 (0.95–1.01)	0.27
Excision	Complete	415	1 (reference)	—	1 (reference)	—
	Uncertain	100	1.49 (0.96–2.31)	0.074	1.65 (1.06–2.56)	0.027
	Incomplete	97	1.68 (1.09–2.58)	0.019	1.94 (1.25–3.02)	0.0031
	Trend test			0.0095		0.0012
Size	mm (mean)	15.7	1.03 (1.02–1.05)	0.0002	1.02 (1.01–1.04)	0.012
Grade	Low	34	1 (reference)	—	1 (reference)	—
	Intermediate	102	1.43 (0.48–4.25)	0.52	0.89 (0.28–2.83)	0.84
	High	476	2.15 (0.79–5.84)	0.13	1.01 (0.32–3.22)	0.99
	Trend test			0.036		0.74
Necrosis	No	45	1 (reference)	—	1 (reference)	—
	Yes	567	1.85 (0.81–4.19)	0.14	1.17 (0.45–3.05)	0.75
Inflammation	No	123	1 (reference)	—	1 (reference)	—
	Yes	489	1.96 (1.16–3.31)	0.011	1.39 (0.77–2.50)	0.27
Radiotherapy	No	388	1 (reference)	—	1 (reference)	—
	Yes	224	0.33 (0.21–0.51)	<0.0001	0.30 (0.19–0.47)	<0.0001
Tamoxifen	No	288	1 (reference)	—	1 (reference)	—
	Yes	324	0.65 (0.46–0.92)	0.015	0.71 (0.50–1.01)	0.056

Note: Endpoint: IBE; n = 612; events = 133; univariate analyses restricted to the same sample size as available for multivariate analyses.