Table 2

Clinicopathological characteristics of 193 women with node-negative breast cancer by Ki67 category

Patient or tumour characteristic		Ki67<10 (n=70)		Ki67≥10 (n=123)		All (n=193)
Patient or tumour characteristic	p Value*	n	%	n	%	n	%
Age at diagnosis, years	0.004
<35		0	0	12	9.8	12	6.2
≥35		70	100	111	90.2	181	93.8
Tumour size, mm	0.009
≤10		20	29	13	10.6	33	17.2
11–15		17	24.6	47	38.2	64	33.3
16–20		18	26.1	32	26	50	26
>20		14	20.3	31	25.2	45	23.4
Histological grade	<0.001
1		43	61.4	21	17.1	64	33.2
2		26	37.1	40	32.5	66	34.2
3		1	1.4	62	50.4	63	32.6
Oestrogen receptor status	<0.001
Positive		67	97.1	82	67.8	149	78.4
Negative		2	2.9	39	32.2	41	21.6
LVI	0.575
No		54	79.4	87	71.9	141	74.6
Yes†		14	20.6	34	28.1	48	25.4
Mitotic index	<0.001
<10		66	94.3	60	48.8	126	65.3
≥10		4	5.7	63	51.2	67	34.7
CK5/6	0.001
Negative		58	84.1	72	60	130	68.8
Positive		11	15.9	48	40	59	31.2
HER2	0.004
Negative		70	100	108	90.0	178	93.7
Positive		0	0	12	10.0	12	6.3
Contralateral	0.749
Yes		3	4.3	8	6.5	11	5.7
No		67	95.7	115	93.5	182	94.3

*p Values are for comparison of categories of each variable by Ki67 using the Pearson χ² test or Fisher's exact test; 193 of 203 cases were evaluable for Ki67.
†Includes three indeterminate cases.
CK, cytokeratin; HER2, human epidermal growth factor 2; LVI, lymphovascular invasion.