Table 3.

Concordance Rates by Clinical Factors (all patients)

Subgroup	HER2 Status				P
	Concordant(n = 139)		Discordant(n = 43)
	No.	%	No.	%
Trastuzumab
None	78	74	28	26	.296
Before biopsy	61	80	15	20
Timing of metastasis diagnosis
At presentation	30	88	4	12	.077
At recurrence	109	74	39	26
Metastatic location
Local	53	72	21	28	.212
Distant	86	80	22	20
Hormone receptor status
Positive	79	77	23	23	.865
Negative	58	74	20	26
Unknown	2
Chemotherapy with or without trastuzumab
None	36	90	4	10	.022
Before biopsy	103	73	39	27
Time from diagnosis of breast cancer to biopsy, years
≤ 5	95	78	27	22	.498
> 5	44	73	16	27
Years of breast cancer diagnosis
1997-2004	102	76	32	24	.893
2005-2008	37	77	11	23
	(n = 78)		(n = 28)
Chemotherapy without trastuzumab*
None	36	90	4	10
Before biopsy	42	64	24	36

Abbreviation: HER2, human epidermal growth factor receptor 2.

^*Among 106 patients who had chemotherapy without trastuzumab, the total number of patients with HER2 status concordance was 78; total with discordance, 28.