Table 6.

Univariate and Multivariate Cox Proportional Hazards Models Predicting Overall Survival

Characteristic	Univariate Analysis		Multivariate Analysis
	HR	P Value	HR	P Value	95% CI
Age
< 50 y	Referent		Referent
≥50 y	0.4	<0.0001	0.6	0.01	0.4–0.9
IM drainage	0.9	0.5
UOQ tumor location	1.0	0.997
Medial tumor location	1.1	0.7
LVI	1.5	0.03	1.6	0.03	1.04–2.3
Nuclear grade
1	Referent
2	0.9	0.6	0.8	0.5	0.5–1.4
3	1.7	0.04	1.2	0.5	0.7–2.2
Tumor stage
T1	Referent		Referent
T2	1.6	0.007	1.5	0.03	1.04–2.1
T3	2.3	0.046	2.2	0.07	0.9–5.4
Negative ER status	2.4	<0.0001	2.8	<0.0001	2.0–3.9
Negative PR status	1.3	0.06	0.8	0.2	0.5–1.1
Negative HER-2 status	0.9	0.5
Tumor histology
IDC	Referent
ILC	0.9	0.6
IDC and ILC	0.8	0.5
Other	1.3	0.4
Number of positive LNsa	1.1	0.003	1.3	0.03	1.02–1.7

HR indicates hazards ratio; CI, confidence interval; IM, internal mammary; UOQ, upper outer quadrant; LVI, lymphovascular invasion; ER, estrogen receptor; PR, progesterone receptor; IDC, invasive ductal carcinoma; ILC, invasive lobular carcinoma; LN, lymph node.

^aAs a continuous variable.