Table 2.

Results of Cox proportional hazards models without transform. Hazard ratios (95% confidence intervals), values > 1 indicate increased risk of death.

	Overall mortality		Breast cancer specific mortality
	N0	N+	N0	N+
SEER central area	1.00 (0.95–1.05)	0.93 (0.87–0.98)	1.03 (0.94–1.13)	0.92 (0.86–0.99)
SEER western area	0.92 (0.88–0.97)	0.87 (0.82–0.92)	0.82 (0.75–0.90)	0.86 (0.80–0.91)
Race black	1.38 (1.27–1.49)	1.42 (1.31–1.52)	1.37 (1.21–1.55)	1.44 (1.31–1.57)
Married	0.75 (0.72–0.78)	0.82 (0.78–0.86)	0.88 (0.81–0.95)	0.91 (0.86–0.97)
Inner quadrant	1.09 (1.04–1.15)	1.16 (1.08–1.24)	1.32 (1.21–1.44)	1.3 (1.19–1.41)
Ductal histology	1.14 (1.09–1.2)	1.11 (1.04–1.17)	1.44 (1.31–1.58)	1.12 (1.05–1.21)
ER negative	1.39 (1.28–1.5)	1.52 (1.41–1.64)	1.58 (1.4–1.78)	1.58 (1.44–1.73)
PR negative	1.11 (1.03–1.18)	1.27 (1.18–1.36)	1.36 (1.21–1.52)	1.39 (1.28–1.52)
Grade 3–4	1.23 (1.17–1.29)	1.34 (1.28–1.41)	1.6 (1.48–1.73)	1.48 (1.39–1.57)
BCS	1.12 (1.02–1.24)	0.96 (0.86–1.07)	1.01 (0.84–1.20)	0.98 (0.86–1.12)
Radiotherapy	1.12 (0.96–1.29)	0.89 (0.83–0.95)	1.31 (1.08–1.6)	0.91 (0.84–0.99)
BCSxRT	0.61 (0.51–0.73)	0.92 (0.8–1.06)	0.63 (0.48–0.82)	0.88 (0.74–1.04)
Year Diagnosis (continuous, year)	0.98 (0.97–0.99)	0.96 (0.95–0.97)	0.92 (0.91–0.94)	0.94 (0.93–0.95)
Age at Diagnosis (continuous, year)	1.05 (1.05–1.05)	1.02 (1.02–1.03)	1.00 (1.00–1.01)	1.00 (1.00–1.01)
Tumor size (continuous, mm)	1.03 (1.03–1.03)	1.02 (1.02–1.02)	1.05 (1.04–1.05)	1.02 (1.02–1.03)
Number positive nodes (continuous, n)	(-)	1.07 (1.07–1.08)	(-)	1.09 (1.08–1.09)
Number nodes examined (continuous, n)	0.99 (0.99–0.99)	0.98 (0.97–0.98)	0.99 (0.99–1.00)	0.97 (0.96–0.97)

BCS = breast conserving surgery, BCSxRT = breast conserving surgery and radiotherapy, ER = estrogen receptor, N0 = node negative, N+ = node positive, PR = progesterone receptor, SEER = Surveillance, Epidemiology, and End Results Program.