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Table 1 Patient and tumor characteristics

From: Artificial neural network models to predict nodal status in clinically node-negative breast cancer

  All (n = 800) N0 (n = 514) N1 (n = 232) N2 (n = 54) p value
Agea, years 64 (24–92) 64 (33–92) 63 (24–92) 62 (26–85) 0.039b
 Missing 0 0 0 0  
BMIa, kg/m2 25 (16–49) 26 (16–44) 26 (16–46) 26 (20–49) 0.569b
 Missing 41 24 13 4  
Menopausal status      0.011c
 Premenopausal 130 (17) 70 (14) 48 (22) 12 (24)  
 Postmenopausal 628 (83) 414 (86) 175 (78) 39 (76)  
 Missing 42 30 9 3  
Mode of detection      < 0.001c
 Mammographic screening 457 (57) 321 (63) 113 (49) 23 (43)  
 Symptomatic presentation 343 (43) 193 (38) 119 (51) 31 (57)  
 Missing 0 0 0 0  
Bilateral cancer      0.255c
 Absent 770 (96) 499 (97) 222 (96) 49 (91)  
 Present 30 (4) 15 (3) 10 (4) 5 (9)  
 Missing 0 0 0 0  
Multifocality      < 0.001c
 Absent 610 (77) 418 (82) 161 (71) 31 (61)  
 Present 179 (23) 92 (18) 67 (29) 20 (39)  
 Missing 11 4 4 3  
Tumor site, quadrants of breast      0.170d
 Central C501 22 (3) 14 (3) 6 (3) 2 (4)  
 Upper inner C502 108 (14) 78 (15) 25 (11) 5 (9)  
 Lower inner C503 46 (6) 32 (6) 12 (5) 2 (4)  
 Upper outer C504 266 (33) 165 (32) 86 (37) 15 (28)  
 Lower outer C505 84 (11) 43 (8) 31 (13) 10 (19)  
 Overlapping lesions: 3, 6, 9, 12 o’clock 274 (34) 182 (35) 72 (31) 20 (37)  
 Missing 0 0 0 0  
Tumor sizea, mm 15 (0.5–90) 13 (0.5–70) 17 (0.9–90) 23 (6–70) < 0.001b
 Missing 1 0 1 0  
Histological type 800 514 232 54 0.010 e
 Ductal 640 (80) 408 (79) 195 (84) 37 (69)  
 Lobular 101 (13) 60 (12) 27 (12) 14 (26)  
 Other 59 (7) 46 (9) 10 (4) 3 (6)  
 Missing 0 0 0 0  
Histological grade      0.003c
 I 197 (25) 142 (28) 48 (21) 7 (13)  
 II 366 (46) 231 (46) 106 (46) 29 (54)  
 III 229 (29) 134 (26) 77 (33) 18 (33)  
 Missing 8 7 1 0  
Vascular invasion      < 0.001c
 Absent 545 (85) 401 (94) 124 (72) 20 (37)  
 Present 94 (15) 28 (7) 48 (28) 18 (33)  
 Missing 161 85 60 16  
ER status      0.020 c
 Positive 729 (91) 459 (90) 218 (94) 52 (96)  
 Negative 69 (9) 53 (10) 14 (6) 2 (4)  
 Missing 2 2 0 0  
PR status      0.075c
 Positive 673 (84) 421 (82) 206 (89) 46 (85)  
 Negative 125 (16) 91 (18) 26 (11) 8 (15)  
 Missing 2 2 0 0  
HER2 status      0.208c
 Positive 86 (12) 51 (11) 27 (13) 15 (16)  
 Negative 647 (88) 422 (89) 184 (87) 41 (84)  
 Missing 67 41 21 5  
Ki-67 a, % 15 (0–94) 14 (0–94) 17 (1–81) 20 (3–76) 0.001b
 Missing 48 29 16 3  
  1. p values refer to the comparisons between N0, N1 and N2
  2. Column percentages are given for categorical variables unless indicated otherwise
  3. Percentage have been rounded and may therefore not total 100
  4. Abbreviations: N0 Lymph node-negative, N1 Lymph node metastasis involving 1–3 nodes, N2 Lymph node metastasis involving at least 4 nodes, BMI Body mass index, ER Estrogen receptor, PR Progesterone receptor, HER2 Human epidermal growth factor receptor
  5. amedian (range)
  6. bJonckheere-Terpstra Test
  7. cχ2 test for trend
  8. dPearson χ2 test
  9. eFisher’s exact test