Table 4. Tumour response of patients with KRAS WT (n=54) and KRAS MT (n=10) metastatic or locally advanced colorectal cancer treated with anti-EGFR therapy according to ROC curve based cut-off values of EGFR GCN and chromosome 7 number evaluated by SISH.

	Treatment response					PFS					OS
	Total no. of patients	PR	SD	PD	P-value Fisher's exact test	PFS time median (days)	P-value log-rank test	P-value Cox testa	HR	95% CI	OS time median (days)	P-value log-rank test	P-value Cox testa	HR	95% CI
KRAS WT and MT patients	54
KRAS status
KRAS WT	44	11 (25)	15 (34.1)	18 (40.9)	NS	151	0.01	0.01	0.40	0.20–0.84	352	0.3	0.3	0.67	0.32–1.38
KRAS MT	10	0	3 (30)	7 (70)		81					249
EGFR GCN status
EGFR GCN ⩾4.0	34	10 (29.4)	15 (44.1)	9 (26.5)	0.0006	224	<0.0001	<0.0001	0.21	0.10–0.43	483	0.004	0.006	0.41	0.22–0.77
EGFR GCN <4.0	20	1 (5)	3 (15)	16 (80)		84					134
KRAS WT patients
EGFR GCN
⩾4.0	28	10 (35.7)	13 (46.4)	5 (17.9)	0.0002	244	<0.0001	<0.0001	0.17	0.07–0.39	598	0.001	0.002	0.32	0.16–0.66
<4.0	16	1 (6.2)	2 (12.5)	13 (81.3)		84					134
Chromosome 7 number
⩾4.5	24	9 (37.5)	10 (41.7)	5 (20.8)	0.009	214	0.2	0.2	0.67	0.35–1.29	520	0.1	0.1	0.56	0.28–1.13
<4.5	20	2 (10)	5 (25)	13 (65)		94					225
KRAS MT patients
EGFR GCN
⩾4.0	6	0	2 (33.3)	4 (66.7)	NS	94	NS				369	NS
<4.0	4	0	1 (25)	3 (75)		77					134
Chromosome 7 number
⩾4.5	6	0	2 (33.3)	4 (66.7)	NS	94	NS				369	NS
<4.5	4	0	1 (25)	3 (75)		77					134

Abbreviations: CI=confidence interval; CR=complete response; EGFR=epidermal growth factor receptor; GCN=gene copy number; HR=hazards ratio; MT=mutated; NS=not significant; OS=overall survival; PD=progressive disease; PFS=progression-free survival; PR=partial response; ROC= receiver operating characteristic; SD=stable disease; SISH=silver in situ hybridisation; WT=wild type.

^aCox proportional hazards regression model. Treatment response values are given n (%). Significant P-values are shown in bold type.