Table 1. Baseline characteristics of women screened and referred at non-blinded and blinded double reading.
|
Screened population |
Referred women |
|||||
|---|---|---|---|---|---|---|
| Non-blinded (n=42 996) | Blinded (n=44 491) | P-value | Non-blinded (n=1235) | Blinded (n=1474) | P-value | |
| Age distribution, no (%) | 0.49 | 0.91 | ||||
| 50–59 | 22 704 (52.8) | 23 469 (52.7) | 653 (52.9) | 778 (52.8) | ||
| 60–69 | 14 537 (33.8) | 14 949 (33.6) | 417 (33.8) | 491 (33.3) | ||
| 70–75 | 5755 (13.4) | 6073 (13.6) | 165 (13.3) | 205 (13.9) | ||
| Previous breast surgery, no (%) | 0.58 | 0.20 | ||||
| Yes | 3354 (7.8) | 3516 (7.9) | 129 (10.4) | 177 (12.0) | ||
| No | 39 642 (92.2) | 40 975 (92.1) | 1106 (89.6) | 1297 (88.0) | ||
| Hormone replacement therapy, no. (%) | 0.74 | 0.82 | ||||
| Yes | 2064 (4.8) | 2157 (4.8) | 55 (4.5) | 63 (4.3) | ||
| No | 40 932 (95.2) | 42 334 (95.2) | 1180 (95.5) | 1411 (95.7) | ||
| Family history of breast cancera, no (%) | Not available | Not available | 0.59 | |||
| Yes | 149 (12.1) | 168 (11.4) | ||||
| No | 1086 (87.9) | 1306 (88.6) | ||||
| Screening round, no (%) | 0.85 | 0.15 | ||||
| Initial screen | 4784 (11.1) | 4968 (11.2) | 309 (25.0) | 334 (22.7) | ||
| Subsequent screen | 38 212 (88.9) | 39 523 (88.8) | 926 (75.0) | 1140 (77.3) | ||
| Mammographic breast density | Not available | Not available | 0.83 | |||
| 0–50% | 1014 (82.1) | 1215 (82.4) | ||||
| >50% | 221 (17.9) | 259 (17.6) | ||||
| Lesion abnormality at latest screen, no (%) | Not applicable | Not applicable | 0.34 | |||
| Suspicious mass | 718 (58.1) | 827 (56.1) | ||||
| Suspicious microcalcifications | 334 (27.0) | 445 (30.2) | ||||
| Suspicious mass with microcalcifications | 85 (6.9) | 95 (6.4) | ||||
| Asymmetry | 22 (1.8) | 28 (1.9) | ||||
| Architectural distortion | 72 (5.8) | 78 (5.3) | ||||
| Other mammographic abnormality | 4 (0.3) | 1 (0.1) | ||||
a
At least one first-degree relative with a diagnosis of breast cancer before the age of 50 years or at least two second-degree relatives with breast cancer.