Table 2.

Odds ratios and 95% confidence intervals from multinomial logistic regression models comparing first course therapy groups with breast conserving surgery (BCS) as referent group

Characteristic	BCS (N = 2689)	BCS + radiation (N = 3978)	Unilateral mastectomy (N = 2322)	Bilateral mastectomy (N = 448)
KP Region
1	1.0	1.20 (0.97-1.49)	1.16 (0.91-1.48)	2.76 (1.88-4.04)
2	1.0	2.10 (1.47-2.99)	2.19 (1.49-3.22)	3.69 (2.07-6.59)
3	1.0	1.31 (0.96-1.78)	0.75 (0.52-1.08)	0.32 (0.08-1.33)
4		[Referent]	[Referent]	[Referent]
5	1.0	3.00 (2.24-4.02)	1.93 (1.39-2.70)	4.59 (2.87-7.34)
6	1.0	0.62 (0.56-0.70)	0.75 (0.66-0.85)	1.39 (1.09-1.78)
Age at diagnosis
<50 years		[Referent]	[Referent]	[Referent]
50-59 years	1.0	1.12 (0.96-1.30)	0.79 (0.67-0.93)	0.54 (0.42-0.70)
60-69 years	1.0	0.98 (0.84-1.14)	0.69 (0.59-0.82)	0.29 (0.22-0.39)
70+ years	1.0	0.54 (0.45-0.63)	0.55 (0.46-0.65)	0.08 (0.05-0.13)
Race/Ethnicity
White		[Referent]	[Referent]	[Referent]
African American	1.0	0.88 (0.74-1.04)	0.91 (0.75-1.10)	0.56 (0.39-0.80)
Asian	1.0	1.11 (0.95-1.30)	1.62 (1.37-1.91)	0.52 (0.36-0.76)
Hispanic	1.0	1.30 (1.08-1.56)	1.16 (0.94-1.42)	0.69 (0.48-1.00)
Census Tract % College Educated (Quintiles)
1: 32.3% - 78.8%	1.0	1.11 (0.94-1.30)	0.99 (0.83-1.19)	1.06 (0.78-1.46)
2: 78.9% - 86.3%	1.0	1.06 (0.90-1.24)	0.77 (0.64-0.92)	0.78 (0.56-1.08)
3: 86.5% - 92.2%	1.0	1.05 (0.89-1.24)	0.88 (0.73-1.05)	0.82 (0.59-1.14)
4: 92.3% - 95.7%	1.0	1.00 (0.84-1.18)	0.76 (0.63-0.92)	0.75 (0.53-1.05)
5 (highest): > 95.7%		[Referent]	[Referent]	[Referent]
Year of Diagnosis	1.0	1.06 (1.04-1.08)	1.00 (0.99-1.02)	1.16 (1.12-1.20)
Comorbidity Index
0		[Referent]	[Referent]	[Referent]
1	1.0	0.84 (0.73-0.96)	1.01 (0.87-1.18)	0.88 (0.66-1.17)
2+	1.0	0.75 (0.62-0.89)	0.95 (0.78-1.16)	0.81 (0.53-1.23)
Nuclear Grade
Low/Intermediate		[Referent]	[Referent]	[Referent]
High	1.0	2.01 (1.80-2.25)	2.70 (2.39-3.06)	2.52 (2.03-3.14)
Unknown	1.0	0.93 (0.79-1.10)	1.16 (0.96-1.40)	1.07 (0.73-1.57)