Table 5.

 Multivariate Cox proportional hazards model for Ki-67 index and treatment interaction for ER positive tumours*

Variable		RFS			BCS
		RR	95% CI	p Value	RR	95% CI	p Value
Ki-67	Intermediate v low + high	0.85	0.50 to 1.46	0.56	0.81	0.51 to 1.69	0.93
Treatment	Tamoxifen v control	0.46	0.29 to 0.74	0.001	0.61	0.36 to 1.02	0.06
Interaction variable	Tamoxifen × Ki-67	2.63	1.19 to 5.82	0.02	2.38	1.01 to 5.63	0.05
MI	2 v 1+3	1.22	0.80 to 1.88	0.35	1.04	0.64 to 1.69	0.88
Treatment	Tamoxifen v control	0.60	0.38 to 0.94	0.02	0.66	0.40 to 1.09	0.10
Interaction variable	Tamoxifen × MI	1.18	0.59 to 2.36	0.64	1.59	0.74 to 3.39	0.23
NHG	3 v 1+2	1.86	1.17 to 2.95	0.008	2.43	1.46 to 4.06	0.001
Treatment	Tamoxifen v control	0.62	0.40 to 0.96	0.03	0.76	0.45 to 1.25	0.28
Interaction variable	Tamoxifen × NHG	0.94	0.46 to 1.92	0.87	0.96	0.44 to 2.05	0.91
Histological type	ILC v IDC	0.70	0.32 to 1.55	0.38	0.88	0.37 to 2.09	0.78
Treatment	Tamoxifen v control	0.59	0.40 to 0.85	0.005	0.75	0.50 to 1.13	0.17
Interaction variable	Tamoxifen × type	1.39	0.44 to 4.39	0.58	1.17	0.33 to 4.09	0.81

*Adjusted for age (continuous), tumour size (T1 v T2), and nodal status (N0 v N+).

BCS, breast cancer survival; CI, confidence interval; IDC, invasive ductal carcinomas; ILC, invasive lobular carcinoma; MI, mitotic index; NHG, Nottingham histological grade; RFS, recurrence free survival; RR, relative risk.