Table 4. Characteristics of Breast Cancers Occurring Within 1 Year of the Screening Examination Among the Study Groups.
| Variable | No./Total No. (%) | ||
|---|---|---|---|
| Mammography Plus Ultrasonography | Mammography Alone (Matched) | Mammography Alone (Overall) | |
| Total | 249 | 470 | 719 |
| Cancer histology | |||
| Noninvasive (DCIS) | 20/42 (47.6) | 77/221 (34.8) | 249/719 (34.6) |
| Invasive | 22/42 (52.4) | 144/221 (65.2) | 470/719(65.4) |
| Ductal | 19/20 (95.0) | 113/141 (80.1) | 384/458 (83.8) |
| Lobular | 1/20 (5.0) | 20/141 (14.2) | 50/458 (10.9) |
| Mixed | 0/20 | 8/141 (5.7) | 24/458 (5.2) |
| Other/unknown | 2 | 3 | 12 |
| Invasive tumor size, mm | |||
| 1-5 | 2/20 (10.0) | 8/140 (5.7) | 48/454 (10.6) |
| 6-10 | 5/20 (25.0) | 37/140 (26.4) | 116/454 (25.6) |
| 11-15 | 3/20 (15.0) | 25/140 (17.9) | 87/454 (19.2) |
| 16-20 | 3/20 (15.0) | 26/140 (18.6) | 74/454 (16.3) |
| >20 | 7/20 (35.0) | 44/140 (31.4) | 129/454 (28.4) |
| Unknown | 2 | 4 | 16 |
| Minimal cancer | |||
| No | 13/41 (31.7) | 95/210 (45.2) | 290/691 (42.0) |
| Yes | 28/41 (68.3) | 115/210 (54.8) | 401/691 (58.0) |
| Unknown | 1 | 11 | 28 |
| Axillary lymph node status | |||
| Negative | 35/41 (85.4) | 183/219 (83.6) | 620/708 (87.6) |
| Positive | 6/41 (14.6) | 36/219 (16.4) | 88/708 (12.4) |
| Unknown | 1 | 2 | 11 |
| AJCC stage | |||
| 0 | 20/41 (48.8) | 77/219 (35.2) | 249/706 (35.3) |
| I | 11/41 (26.8) | 85/219 (38.8) | 297/706 (42.1) |
| II | 8/41 (19.5) | 43/219 (19.6) | 131/706 (18.6) |
| III | 2/41 (4.9) | 13/219 (5.9) | 24/706 (3.4) |
| IV | 0/41 | 1/219 (0.5) | 5/706 (0.7) |
| Unknown | 1 | 2 | 13 |
| Grade of invasive cancer | |||
| 1 | 8/19 (42.1) | 48/138 (34.8) | 173/448 (38.6) |
| 2 | 8/19 (42.1) | 62/138 (44.9) | 191/448 (42.6) |
| 3 | 3/19 (15.8) | 28/138 (20.3) | 84/448 (18.8) |
| Unknown | 3 | 6 | 22 |
| Hormone receptor status of invasive cancer | |||
| ER+ or PR+ | 17/21 (81.0) | 134/142 (94.4) | 426/457 (93.2) |
| ER− and PR− | 4/21 (19.0) | 8/142 (5.6) | 31/457 (6.8) |
| Unknown | 1 | 2 | 13 |
Abbreviation: AJCC, American Joint Committee on Cancer; DCIS, ductal carcinoma in situ; ER, estrogen receptor; PR, progesterone receptor.