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Table 1 Distribution of risk factors and clinicopathological characteristics by tumor subtype

From: Breast cancer risk factors, survival and recurrence, and tumor molecular subtype: analysis of 3012 women from an indigenous Asian population

Characteristic Overall (%) A-like (N = 1016/34%) % B-like (N = 989/33%) % HER2-enriched (N = 387/13%) % Triple-neg. (N = 620/20%) % P valuea
Age, yrs
 Mean (range) 51.6 (19, 91) 52.6 (24–90)   51.1 (19, 90)   51.6 (23, 91)   51.5 (21, 87)   
  < 35 180 (5) 47 4.6 49 5.0 26 6.7 40 6.5 0.01
 35–45 711 (21) 192 18.9 219 22.1 76 19.7 144 23.2  
 45–55 1204 (36) 368 36.2 366 37.0 136 35.1 203 32.7  
 55–65 806 (24) 241 23.7 246 24.9 105 27.1 143 23.1  
 65–75 364 (11) 135 13.3 90 9.1 35 9.1 65 10.5  
  > 75 90 (3) 33 3.3 19 1.9 9 2.3 25 4.0  
Ethnicity
 Chinese 1626 (48) 567 55.8 435 44 180 46.5 275 44.4 < 0.0001
 Malay 801 (24) 204 20.1 263 26.6 104 26.9 155 25  
 Native 928 (28) 245 24.1 291 29.4 103 26.6 190 30.6  
Menarche
  ≤ 12 yrs 1105 (33) 344 34.1 326 33.2 118 30.8 190 30.9 0.20
 13 yrs 1117 (34) 318 31.5 340 34.7 148 38.6 201 32.7  
 14 yrs 548 (16) 163 16.2 167 17 60 15.7 111 18  
  ≥ 15 yrs 559 (17) 184 18.2 148 15.1 57 14.9 113 18.4  
Menopause
  ≤ 50 yrs 428 (29) 146 32.7 128 29.7 38 23.2 87 31.6 0.14
  > 50 yrs 1031 (71) 301 67.3 303 70.3 126 76.8 188 68.4  
Parity
 Nulliparous 745 (22) 242 23.8 224 22.6 77 19.9 128 20.6 0.29
 Parous 2601 (78) 774 76.2 765 77.4 310 80.1 492 79.4  
Age at FFPb, yrs
  < 21 466 (18) 116 15 158 20.7 54 17.4 95 19.3 0.02
 21–24.9 1011 (39) 284 36.7 287 37.5 129 41.6 199 40.5  
 25–30 864 (33) 275 35.5 248 32.4 103 33.2 154 31.4  
  > 30 259 (10) 99 12.8 72 9.4 24 7.7 43 8.7  
Breastfeeding
 No 377 (14) 133 17.2 103 13.5 31 10 64 13 0.01
 Yes 2224 (86) 641 82.9 662 86.5 279 90 428 87  
Breastfeeding duration
  < 6 months 927 (52) 285 54.2 280 51.8 111 49.6 175 51.3 0.40
 6–10 months 374 (21) 112 21.3 122 22.6 48 21.4 62 18.2  
  > 10 months 489 (27) 129 24.5 138 25.6 65 29.0 104 30.5  
BMI, kg/m2
  < 18.5 1253 (39) 373 37.8 336 35.1 163 43.7 240 40.2 0.03
 18.5–24.9 565 (17) 160 16.2 172 18 68 18.2 114 19.1  
 25–29.9 998 (31) 317 32.2 301 31.4 104 27.9 177 29.6  
  ≥ 30 433 (13) 136 13.8 148 15.5 38 10.2 66 11.1  
Family history
 No 2835 (86) 840 84 854 87.8 338 88 516 84.9 0.05
 Yes 468 (14) 160 16 119 12.2 46 12 92 15.1  
Histological grade
 Well diff. 365 (11) 212 20.9 67 6.8 10 2.6 27 4.4 < 0.0001
 Moderately diff. 1790 (55) 781 76.9 442 44.7 180 46.5 238 38.4  
 Poorly diff. 1123 (34) 473 47.8 192 49.6 344 55.5  
Stage
 I 454 (14) 222 22.1 100 10.3 34 8.9 61 10 < 0.0001
 II 1353 (42) 444 44.2 395 40.6 136 35.6 249 40.9  
 III 1005 (31) 241 24 330 33.9 150 39.3 203 33.3  
 IV 421 (13) 78 7.8 139 14.3 57 14.9 91 14.9  
Tumor size
  < 2 cm 2137 (64) 761 75.6 620 63.3 210 54.7 353 57.8 < 0.0001
 2–5 cm 522 (16) 121 12 150 15.3 83 21.6 104 17  
  > 5 cm 660 (20) 125 12.4 209 21.4 91 23.7 154 25.2  
Node status
 0 1517 (46) 566 55.7 368 37.2 146 37.7 272 43.9 < 0.0001
 1 922 (28) 249 24.5 310 31.3 95 24.5 163 26.3  
 2 480 (15) 120 11.8 156 15.8 70 18.1 94 15.2  
  ≥ 3 375 (11) 72 7.1 139 14.1 68 17.6 75 12.1  
Endocrine
 None 1248 (40) 48 5.1 126 14.2 357 97.5 584 97.2 < 0.0001
 Tamoxifen 1456 (47) 687 72.9 591 66.7 7 1.9 15 2.5  
 Aromatase Inhibitor 395 (13) 207 22.0 169 19.1 2 0.6 2 0.3  
Chemotherapy
 No 799 (24) 371 37.3 177 18.3 62 16.4 95 15.5 < 0.0001
 Yes 2483 (76) 625 62.7 789 81.7 317 83.6 519 84.5  
Surgery
 No 389 (12) 80 10.2 106 15.8 53 19.4 87 16.3 < 0.0001
 Yes 2841 (88) 913 89.8 833 84.2 312 80.6 519 83.7  
Radiotherapy
 No 800 (26) 261 27.7 218 24.6 79 23.9 149 26.4 0.01
 Yes 2235 (74) 683 72.3 669 75.4 252 76.1 416 73.6  
  1. Breast cancer subtypes were defined based on 2013 St Gallen criteria by using hormone receptor (ER and PR) and HER2 in conjunction with histologic grade. In bold are statistically significant P values (< 0.05)
  2. aP values are for chi-square tests
  3. bFFP first full-term pregnancy