Table 2 Descriptive statistics of distributions of tumor characteristics comparing interval cancers to screen-detected cancers, interval cancers to screen-detected cancers limited to nondense breasts and interval cancers to screen-detected cancers limited to dense breasts
From: Mammographic density and survival in interval breast cancers
|  | All (n= 1,400) | Nondense, PD <25% (n= 1,055) | Dense, PD ≥25% (n= 345) | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Â | SD cancer (n= 1,115) | IC (n= 285) | Pvalue | SD cancer (n= 867) | IC (n= 188) | Pvalue | SD cancer (n= 248) | IC (n= 97) | Pvalue |
Mean tumor size (mm) | 14.4 | 20.5 | <0.001 | 14.2 | 19.6 | <0.001 | 15.2 | 22.4 | <0.001 |
Lymph node metastasis, n (%) | Â | Â | <0.001 | Â | Â | <0.001 | Â | Â | 0.001 |
   Positive | 240 (22%) | 109 (39%) |  | 190 (22%) | 72 (39%) |  | 50 (20%) | 37 (38%) |  |
   Negative | 856 (78%) | 171 (61%) |  | 660 (78%) | 111 (61%) |  | 196 (80%) | 60 (62%) |  |
ER status, n (%) | Â | Â | 0.020 | Â | Â | 0.054 | Â | Â | 0.150 |
   Positive | 627 (83%) | 162 (76%) |  | 492 (82%) | 99 (75%) |  | 135 (84%) | 63 (77%) |  |
   Negative | 131 (17%) | 52 (24%) |  | 106 (18%) | 33 (25%) |  | 25 (16%) | 19 (23%) |  |
PR status, n (%) | Â | Â | 0.008 | Â | Â | 0.018 | Â | Â | 0.133 |
   Positive | 536 (72%) | 130 (62%) |  | 420 (71%) | 78 (60%) |  | 116 (74%) | 52 (65%) |  |
   Negative | 211 (28%) | 79 (38%) |  | 171 (29%) | 51 (40%) |  | 40 (26%) | 28 (35%) |  |
Grade, n (%) | Â | Â | <0.001 | Â | Â | 0.008 | Â | Â | 0.012 |
   1 | 147 (20%) | 20 (11%) |  | 116 (20%) | 15 (14%) |  | 31 (19%) | 5 (6%) |  |
   2 | 333 (45%) | 71 (37%) |  | 265 (45%) | 40 (36%) |  | 68 (42%) | 31 (39%) |  |
   3 | 268 (36%) | 99 (52%) |  | 205 (35%) | 56 (50%) |  | 63 (39%) | 43 (54%) |  |
Histological classification, n (%) | Â | Â | 0.703 | Â | Â | 0.872 | Â | Â | 0.441 |
   Ductal | 813 (73%) | 206 (74%) |  | 640 (74%) | 134 (72%) |  | 173 (71%) | 72 (76%) |  |
   Lobular | 125 (11%) | 35 (13%) |  | 92 (11%) | 22 (12%) |  | 33 (13%) | 13 (14%) |  |
   Other | 173 (16%) | 39 (14%) |  | 134 (15%) | 29 (16%) |  | 39 (16%) | 10 (11%) |  |
Proliferation rate | Â | Â | <0.001 | Â | Â | <0.001 | Â | Â | 0.523 |
   High | 108 (25%) | 52 (42%) |  | 83 (25%) | 36 (48%) |  | 25 (28%) | 16 (33%) |  |
   Low | 316 (75%) | 71 (58%) |  | 252 (75%) | 39 (52%) |  | 64 (72%) | 32 (67%) |  |