Table 2. Multivariable cox proportional hazards analysis of clinicopathologic factors associated with survival, stratified by histology types.

	ILC (n = 85,048)				IDC (n = 711,287)
Factor	HR	P	95% CI		HR	P	95% CI
Age at diagnosis, years
<40	Referent				Referent
40–60		NS	0.64	1.42	1.20	<0.0001	1.09	1.31
>60		NS	1.00	2.19	2.92	<0.0001	2.67	3.19
Marital status
Single	Referent				Referent
Married	0.71	<0.0001a	0.64	0.80	0.63	<0.0001a	0.61	0.65
Tumor site(s)
Only one site(left or right)	Referent				Referent
Two or more sites		NS	0.46	1.20		NS	0.57	1.04
Tumor size, mm
< = 20	Referent				Referent
21–40	1.37	<0.0001c	1.19	1.59	1.45	<0.0001c	1.39	1.51
> = 41	1.28	<0.0001c	1.09	1.51	1.49	<0.0001c	1.41	1.57
Tumor stage
I-II	Referent				Referent
III-IV	1.79	<0.0001c	1.41	2.29	1.16	0.001c	1.06	1.26
Tumor grade
I	Referent				Referent
II	1.34	<0.0001a	1.17	1.54	1.16	<0.0001a	1.10	1.21
III	1.83	<0.0001a	1.53	2.17	1.58	<0.0001a	1.51	1.67
Undifferentiated		NSa	0.75	4.45	1.75	<0.0001a	1.45	2.11
Breast–AdjustedAJCC 6th T
T0	Referent				Referent
Tis		NSa	0.08	1.68		NSa	0.54	2.76
T1-2		NSa	0.01	2.18	3.43	0.005a	1.45	8.13
T3-4		NSa	0.34	7.07	4.17	0.001a	1.85	9.44
Any T,Mets		NSa	0.15	3.81		NSa	0.71	4.16
Breast–AdjustedAJCC 6th N
N0	Referent				Referent
N1		NSa	0.77	1.14	0.87	<0.0001	0.81	0.93
N2		NSa	0.69	1.26	0.89	0.023	0.80	0.98
N3		NSa	0.80	1.22		NSa	0.95	1.12
NX		NSa	0.73	1.16	1.12	0.032	1.01	1.24
Lymph node, positive counts
Negative	Referent				Referent
1–3	2.50	<0.0001a	1.19	3.27	1.62	<0.0001a	1.50	1.76
4–10	3.95	<0.0001a	2.78	5.61	2.38	<0.0001a	2.15	2.65
>10	5.98	<0.0001a	4.35	7.98	3.11	<0.0001a	2.78	3.46
Positive, counts unknown	4.68	<0.0001a	3.39	6.48	2.10	<0.0001a	1.89	2.34
No examined nodes	6.95	<0.0001a	3.46	13.9	3.12	<0.0001a	2.50	3.91
Breast–AdjustedAJCC 6th M
M0	Referent				Referent
M1	3.11	<0.0001	2.62	3.71	2.68	<0.0001	2.55	2.83
MX		NS	0.93	1.97		NS	0.93	1.14
ER status
Positive	Referent				Referent
Negative	2.14	<0.0001a	1.82	2.52	1.87	<0.0001a	1.82	1.92
Borderline	5.24	<0.0001a	1.95	14.1	1.93	<0.0001a	1.48	2.52
PR status
Positive	Referent				Referent
Negative	2.08	<0.0001a	1.89	2.29	1.70	<0.0001a	1.65	1.74
Borderline	2.51	<0.0001a	1.51	4.20	1.28	0.007a	1.07	54
ER/PR status
ER+/PR+	Referent				Referent
ER+/PR-	1.98	<0.0001b	1.79	2.20	1.37	<0.0001b	1.32	1.43
ER-/PR+	2.55	<0.0001b	1.52	4.29	2.02	<0.0001b	1.47	2.23
ER-/PR-	1.95	<0.0001b	1.81	2.11	1.79	<0.0001b	1.76	1.83
Cancer directed surgery
Not performed	Referent				Referent
Performed	0.16	<0.0001a	0.15	0.17	0.17	<0.0001a	0.17	0.17
Surgery category
Mastectomy	Referent				Referent
Breast conserving surgery	0.69	<0.0001a	0.66	0.71	0.63	<0.0001a	0.62	0.64
Radiation
Not performed	Referent				Referent
Performed	0.73	<0.0001a	0.65	0.82	0.58	<0.0001a	0.56	0.60

HR, hazard ratio; CI, confidence interval; NS, not significant; ILC, invasive lobular carcinoma; IDC, invasiveductal carcinoma;ER, estrogen receptor; PR, progesterone receptor; -,negative; +, positive; NS, not significant.

^a Calculated after exclusion of patients in the Unknown category;

^b Calculated after exclusion of patients in the Borderline or Unknown category.

^cCalculated after exclusion of patients in the no tumor, stage 0 or Unknown category.