Table 2.

Breast cancer-specific mortality associated with percentage of tumor cell nuclei positively stained for estrogen receptor

% of cells staining	Number of women	Number of deaths	Adjusted HR (95% CI)
			Model 1 a	Model 2 b
Overall
<1 (ER-negative)	506	157	Referent	Referent
≥1 (ER-positive)	698	115	0.53 (0.41 to 0.68)	0.64 (0.48 to 0.85)
1 to 39	117	27	0.81 (0.53 to 1.24)	0.93 (0.60 to 1.43)
40 to 59	118	18	0.55 (0.34 to 0.91)	0.66 (0.39 to 1.12)
60 to 79	193	31	0.50 (0.33 to 0.74)	0.57 (0.38 to 0.88)
80 to 100	270	39	0.43 (0.30 to 0.62)	0.52 (0.35 to 0.78)
Trend			Ptrend <0.0001	Ptrend = 0.0003
Trend in women with ER-positive tumors only			Ptrend = 0.004	Ptrend = 0.006
Per 10% increase			0.92 (0.89 to 0.95)	0.94 (0.91 to 0.97)
Per 10% increase in women with ER-positive tumors only			0.91 (0.84 to 0.99)	0.91 (0.84 to 0.99)
White women
<1 (ER-negative)	251	69	Referent	Referent
≥1 (ER-positive)	430	62	0.42 (0.29 to 0.61)	0.56 (0.36 to 0.87)
1 to 39	75	18	0.81 (0.46 to 1.43)	1.04 (0.57 to 1.91)
40 to 59	66	10	0.46 (0.22 to 0.94)	0.65 (0.30 to 1.43)
60 to 79	123	17	0.37 (0.21 to 0.66)	0.47 (0.25 to 0.86)
80 to 100	166	17	0.28 (0.16 to 0.50)	0.39 (0.21 to 0.73)
Trend			Ptrend <0.0001	Ptrend = 0.0004
Trend in women with ER-positive tumors only			Ptrend = 0.001	Ptrend = 0.002
Per 10% increase			0.88 (0.84 to 0.93)	0.91 (0.86 to 0.96)
Per 10% increase in women with ER-positive tumors only			0.85 (0.76 to 0.96)	0.86 (0.76 to 0.96)
Black women
<1 (ER-negative)	255	88	Referent	Referent
≥1 (ER-positive)	268	53	0.56 (0.39 to 0.81)	0.62 (0.42 to 0.94)
1 to 39	42	9	0.56 (0.28 to 1.15)	0.63 (0.30 to 1.29)
40 to 59	52	8	0.50 (0.24 to 1.06)	0.55 (0.25 to 1.21)
60 to 79	70	14	0.60 (0.33 to 1.08)	0.65 (0.35 to 1.21)
80 to 100	104	22	0.56 (0.34 to 0.93)	0.64 (0.37 to 1.10)
Trend			Ptrend = 0.007	Ptrend = 0.06
Trend in women with ER-positive tumors only			Ptrend = 0.54	Ptrend = 0.67
Per 10% increase			0.94 (0.90 to 0.98)	0.95 (0.91 to 1.00)
Per 10% increase in women with ER-positive tumors only			0.98 (0.85 to 1.12)	1.00 (0.87 to 1.14)
Homogeneity between white women and black women
ER-positive versus ER-negative			Phomogeneity = 0.56	Phomogeneity = 0.55
Trend			Phomogeneity = 0.13	Phomogeneity = 0.12
Trend in women with ER-positive tumors only			Phomogeneity = 0.05	Phomogeneity = 0.02
Per 10% increase			Phomogeneity = 0.16	Phomogeneity = 0.15
Per 10% increase in women with ER-positive tumors only			Phomogeneity = 0.06	Phomogeneity = 0.02

CI, confidence interval; ER, estrogen receptor; HR, hazard ratio.

^aMultivariable Cox proportional hazards regression models using age (in days) as the time metric stratified by age (in years) and adjusted for race (white, black), study site (Detroit, Los Angeles), tumor stage (localized, non-localized).

^bAdditionally adjusted for histologic grade (low, intermediate, high).