Human epidermal growth factor receptor 2 positive rates in invasive lobular breast carcinoma: The Singapore experience

Table 2 Univariate and multivariate Cox proportional hazard regression analysis for overall survival among all 864 invasive lobular carcinomas patients

Characteristics	Univariate analysis			Multivariate analysis
	HR	95%CI	P value	HR	95%CI	P value
Age (reference: ≤ 50 yr)
> 50 yr	2.32	1.68-3.20	< 0.001	2.17	1.37-3.44	< 0.001
Ethnicity (reference: Chinese)			< 0.0011			0.0011
Indian	2.53	1.62-3.94	< 0.001	3.41	1.78-6.54	< 0.001
Malay	0.95	0.50-1.82	0.889	0.98	0.42-2.29	0.961
Others	0.40	0.15-1.08	0.070	0.64	0.19-2.12	0.462
ER (reference: Negative)
Positive	0.74	0.44-1.24	0.255
PR (reference: Negative)
Positive	0.62	0.44-0.87	0.005	0.57	0.35-0.91	0.018
HER2 (reference: Negative)
Positive	1.87	1.21-2.90	0.005	2.14	1.16-3.95	0.016
Tumour size (reference: ≤ 2 cm)
> 2 cm	2.43	1.45-4.06	< 0.001
Tumour stage (reference: Stage 1)			< 0.0011			< 0.0011
Stage 2	2.33	1.09-4.99	0.030	1.75	0.76-4.03	0.191
Stage 3	6.98	3.42-14.25	< 0.001	4.52	2.06-9.89	< 0.001
Stage 4	61.82	29.73-128.57	< 0.001	41.74	17.95-97.04	< 0.001
Tumor grade (reference: Grade 1)			< 0.0011			0.0751
Grade 2	1.45	0.83-1.89	0.190	1.05	0.57-1.93	0.877
Grade 3	4.72	2.55-8.74	< 0.001	1.89	0.93-3.84	0.079
Chemotherapy (reference: No)
Yes	0.97	0.69-1.37	0.866
Surgery (reference: No)
Yes	0.06	0.04-0.09	< 0.001
Radiotherapy (reference: No)
Yes	0.89	0.63-1.27	0.518
Molecular subtype (reference: Luminal A)			0.0251			0.0021
Basal	1.52	0.79-2.90	0.206	1.13	0.38-3.29	0.830
HER2 positive	2.08	0.85-5.10	0.108	4.21	1.43-12.44	0.009
Luminal B	1.89	1.16-3.07	0.011	2.52	1.41-4.49	0.002

¹Refers to type 3 P value. HR: Hazard ratio; CI: Confidence interval; HER2: Human epidermal growth factor receptor 2; ER: Estrogen receptor; PR: Progesterone receptor.