Table 5.

Univariate and Multivariate Cox Proportional Hazards Models Predicting Distant Disease–Free 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	1.5	0.07	1.6	0.037	1.03–2.6
UOQ tumor location	1.1	0.8
Medial tumor location	1.3	0.2	1.5	0.2	0.9–2.5
LVI	2.7	<0.0001	2.0	0.005	1.2–3.4
Nuclear grade
1	Referent
2	1.3	0.6	1.1	0.8	0.4–2.7
3	3.8	0.002	2.0	0.1	0.8–5.3
Tumor stage
T1	Referent		Referent
T2	3.4	<0.0001	2.6	<0.0001	1.7–4.1
T3	8.3	<0.0001	4.5	0.001	1.9–10.6
Negative ER status	3.4	<0.0001	3.2	<0.0001	2.0–5.0
Negative PR status	1.6	0.03	0.9	0.7	0.5–1.5
Negative HER-2 status	1.1	0.7
Tumor histology
IDC	Referent
ILC	1.1	0.7
IDC and ILC	0.69	0.4
Other	0.8	0.7
Number of positive LNsa	1.1	<0.0001	1.6	0.006	1.1–2.2

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.