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

Table 4 Univariate and multivariate Cox proportional hazard regression analysis for disease-free 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	1.60	1.11-2.30	0.012	1.63	1.04-2.55	0.033
Ethnicity (reference: Chinese)			0.001
Indian	2.61	1.52-4.48	< 0.001
Malay	0.99	0.48-2.05	0.984
Others	1.99	1.10-3.58	0.022
ER (reference: Negative)
Positive	1.04	0.57-1.90	0.886
PR (reference: Negative)
Positive	0.97	0.65-1.43	0.876
HER2 (reference: Negative)
Positive	1.68	1.04-2.71	0.03
Molecular subtype (reference: Luminal A)			0.2171
Basal	0.98	0.45-2.12	0.965
HER2+	1.69	0.62-4.61	0.304
Luminal B	1.67	0.98-2.83	0.058
Tumour size (reference: ≤ 2 cm)
> 2 cm	2.02	1.26-3.25	0.004
Tumour stage (reference: Stage 1)			< 0.0011			< 0.0011
Stage 2	1.92	1.05-3.53	0.035	1.66	0.83-3.28	0.149
Stage 3	5.66	3.21-9.98	< 0.001	5.26	2.76-10.03	< 0.001
Stage 4	0.62	0.04-10.84	0.745	0.71	0.04-12.61	0.813
Tumor grade (reference: Grade 1)			< 0.0011			0.0131
Grade 2	1.79	1.02-3.16	0.044	1.32	0.73-2.40	0.357
Grade 3	3.72	1.89-7.34	< 0.001	2.69	1.32-5.50	0.007
Chemotherapy (reference: No)
Yes	1.64	1.12-2.42	0.011
Surgery (reference: No)
Yes	0.14	0.08-0.23	< 0.001
Radiotherapy (reference: No)
Yes	1.57	1.05-2.34	0.028

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; HER2+: Human epidermal growth factor receptor 2 positive.