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. Author manuscript; available in PMC: 2018 Apr 1.
Published in final edited form as: Breast Cancer Res Treat. 2017 Jan 24;162(2):317–328. doi: 10.1007/s10549-017-4120-0

Table 1.

Characteristics in invasive breast cancer patients treated with HF-WBI vs. CF-WBI

CF-WBI HF-WBI % HF-WBI AOR (95%CI)* Chi-square
Age at diagnosis
 <40 13,351 361 2.6 1.0 (ref.) 4536.03
 40–44 25,951 925 3.4 1.19 (0.71–2.00)
 45–49 44,993 2,155 4.6 1.48 (0.88–2.48)
 50–54 53,388 3,423 6.0 1.87 (1.12–3.14)
 55–59 58,453 4,453 7.1 2.16 (1.29–3.62)
 60–64 60,338 5,834 8.8 2.54 (1.52–4.26)
 65–69 53,630 6,214 10.4 2.95 (1.76–4.94)
 70–74 37,364 5,304 12.4 3.94 (2.35–6.60)
 75–79 26,585 4,425 14.3 5.17 (3.09–8.67)
 80+ 18,707 4,525 19.5 8.40 (5.01–14.09)

Race/ethnicity
 White 319,902 30,865 8.8 1.0 (ref.) 160.86
 Black 39,426 2,738 6.5 0.91 (0.86–0.96)
 Hispanic 16,337 1,640 9.1 1.07 (1.00–1.15)
 Asian 11,106 1,718 13.4 1.49 (1.40–1.60)
 Other/unknown 5,989 658 9.9 1.07 (0.96–1.20)

Insurance Status
 Not Insured 6,495 461 6.6
 Private Insurance 234,479 17,577 7.0
 Medicaid 19,493 1,395 6.7
 Medicare 123,735 17,513 12.4
 Other Government 3,436 284 7.6
 Insurance Status Unknown 5,122 389 7.1

Charlson/Deyo comorbidity index
 0 344,043 32,351 8.6
 1 41,581 4,401 9.6
 2 7,136 867 10.8

N stage in invasive cancer
 pN0 310,959 33,846 9.8 1.0 (ref.) 1485.91
 pN1 75,522 2,602 3.3 0.38 (0.36–0.40)

T stage in invasive cancer
 <=2.0 cm 307,427 32,227 9.5 1.0 (ref.) 163.30
 2.1–5.0 cm 83,424 5,271 5.9 0.78 (0.75–0.81)

Laterality
 Right 193,956 19,285 9.0 1.0 (ref.) 23.15
 Left 198,465 18,325 8.5 0.94 (0.91–0.96)

Histology in invasive cancer
 Ductal 317,730 29,665 8.5 1.0 (ref.) 26.45
 Lobular 29,400 3,396 10.4 0.92 (0.87–0.97)
 Ductal & lobular 20,102 2,080 9.4 1.10 (1.04–1.17)
 Others 25,528 2,478 8.8 0.95 (0.90–1.01)

Grade
 1 101,086 12,381 10.9 1.0 (ref.) 127.63
 2 161,934 16,123 9.1 0.87 (0.85–0.90)
 3 107,080 6,632 5.8 0.79 (0.76–0.83)

Surgical margin
 Negative 374,676 36,335 8.8 1.0 (ref.) 18.52
 Positive 15,237 1,109 6.8 0.84 (0.78–0.91)

Estrogen receptor & hormone therapy
 Negative 65,749 3,792 5.5 1.0 (ref.) 65.22
 Positive, no hormone therapy 40,986 4,809 10.5 1.24 (1.16–1.32)
 Positive, with hormone therapy 270,010 27,934 9.4 1.05 (1.00–1.11)

Chemotherapy
 No 228,768 30,339 11.7 1.0 (ref.) 456.96
 Yes 154,322 6,405 4.0 0.65 (0.62–0.68)

Facility location
 New England 30,403 2,105 6.5 1.0 (ref.) 2266.99
 Middle Atlantic 59,297 6,956 10.5 1.56 (1.47–1.66)
 South Atlantic 78,068 6,946 8.2 1.51 (1.41–1.61)
 East North Central 75,877 7,377 8.9 1.77 (1.66–1.88)
 East South Central 19,700 1,207 5.8 1.22 (1.12–1.34)
 West North Central 29,442 2,648 8.3 1.45 (1.35–1.56)
 West South Central 20,585 931 4.3 0.83 (0.75–0.92)
 Mountain 15,703 3,152 16.7 4.18 (3.88–4.51)
 Pacific 50,334 5,936 10.5 2.09 (1.96–2.24)

Facility Type & Volume 4051.35
In community cancer program
 <120 82,172 4,623 5.3 1.0 (ref.)
 120–207 70,939 5,825 7.6 1.53 (1.46–1.60)
 208–342 60,871 4,932 7.5 1.49 (1.41–1.56)
 343+ 35,525 3,699 9.4 1.64 (1.55–1.73)
In academic/research program
 <120 5,808 324 5.3 1.0 (ref.)
 120–207 15,381 1,361 8.1 1.73 (1.49–2.02)
 208–342 34,656 4,007 10.4 2.11 (1.83–2.43)
 343+ 45,586 9,287 16.9 3.71 (3.23–4.27)

Median income
 <$30000 53,606 3,934 6.8 1.0 (ref.) 224.52
 $30000–34999 83,090 6,584 7.3 1.07 (1.02–1.13)
 $35,000–45999 105,882 9,537 8.3 1.17 (1.11–1.23)
 $46,000+ 146,574 17,390 10.6 1.37 (1.31–1.45)

Urban/Rural
 Large metropolis (pop. ≥1 million) 201,912 22,897 10.2 1.0 (ref.) 511.32
 Metropolis (pop. <1 million) 126,909 9,411 6.9 0.75 (0.73–0.78)
 Urban (pop. ≥20000) 22,577 1,399 5.8 0.67 (0.63–0.72)
 Urban (pop. 2500–19999) 24,853 2,408 8.8 1.14 (1.06–1.21)
 Rural 5,313 572 9.7 1.34 (1.20–1.50)

Distance to facility
 < 5.0 miles 130,101 12,396 8.7 1.0 (ref.) 155.68
 5.0–9.9 miles 101,001 9,262 8.4 0.89 (0.86–0.92)
 10.0–19.9 miles 86,287 8,096 8.6 0.92 (0.89–0.96)
 20.0–49.9 miles 55,160 5,350 8.8 1.02 (0.97–1.06)
 >=50.0 miles 16,938 2,366 12.3 1.32 (1.24–1.41)
*

Calculated from multivariable logistic regression, adjusting for year of diagnosis and all other variables with adjusted odds ratios in the table. Variables without adjusted odds ratios were not included in the final logistic regression model.

All p-values <0.001

Abbreviations: HF-WBI, hypofractionated whole breast irradiation; CF-WBI, conventional fractionated whole breast irradiation; pop., population; AOR, adjusted odds ratio; CI, confidence interval