Table 1.
Pre-diagnosis subject characteristics and distribution of second breast cancer diagnoses; N (%): WISC DCIS cohort, 1997-2010
| Total N=1,925 | Second breast cancer diagnosis N=162 | No second breast cancer diagnosis N=1,763 | P valuea | |
|---|---|---|---|---|
| Age at diagnosis (years) | 0.13 | |||
| 20-44 | 238 (12.4) | 21 (13.0) | 217 (12.3) | |
| 45-54 | 684 (35.5) | 66 (40.7) | 618 (35.1) | |
| 55-64 | 585 (30.4) | 36 (22.2) | 549 (31.1) | |
| 65-74 | 418 (21.7) | 39 (24.1) | 379 (21.5) | |
| Menopausal status | 0.01 | |||
| Premenopausal | 617 (32.1) | 70 (43.2) | 547 (31.0) | |
| Postmenopausal | 1147 (59.6) | 82 (50.6) | 1065 (60.4) | |
| Unknown | 161 (8.4) | 10 (6.2) | 151 (8.6) | |
| First degree family history of breast cancer | 0.85 | |||
| No | 1380 (71.7) | 114 (70.4) | 1266 (71.8) | |
| Yes | 430 (22.3) | 39 (24.1) | 391 (22.2) | |
| Unknown | 115 (6.0) | 9 (5.6) | 106 (6.0) | |
| Postmenopausal hormone use | <0.01 | |||
| Never | 1287 (66.9) | 129 (79.6) | 1158 (65.7) | |
| Ever | 587 (30.5) | 30 (18.5) | 557 (31.6) | |
| Unknown | 51 (2.7) | 3 (1.9) | 48 (2.7) | |
| Parity | 0.55 | |||
| No births | 270 (14.0) | 27 (16.7) | 243 (13.8) | |
| One birth | 197 (10.2) | 13 (8.0) | 184 (10.4) | |
| Two births | 594 (30.9) | 53 (32.7) | 541 (30.7) | |
| 3+ births | 839 (43.6) | 67 (41.4) | 772 (43.8) | |
| Unknown | 25 (1.3) | 2 (1.2) | 23 (1.3) | |
| Education | 0.37 | |||
| < High school diploma | 93 (4.8) | 5 (3.1) | 88 (5.0) | |
| High school diploma | 736 (38.2) | 64 (39.5) | 672 (38.1) | |
| Some college | 514 (26.7) | 47 (29.0) | 467 (26.5) | |
| College degree | 552 (28.7) | 46 (28.4) | 506 (28.7) | |
| Unknown | 30 (1.6) | 0 | 30 (1.7) | |
| Smoking Status | 0.38 | |||
| Never | 1053 (54.7) | 88 (54.3) | 965 (54.7) | |
| Former | 557 (28.9) | 54 (33.3) | 503 (28.5) | |
| Current | 288 (15.0) | 20 (12.4) | 268 (15.2) | |
| Unknown | 27 (1.4) | 0 | 27 (1.5) | |
| Surgical treatment | <0.01 | |||
| Ipsilateral mastectomy | 593 (30.8) | 41 (25.3) | 552 (31.3) | |
| Bilateral mastectomy | 81 (4.2) | 0 | 81 (4.6) | |
| BCS without radiation | 176 (9.1) | 28 (17.3) | 148 (8.4) | |
| BCS with radiation | 826 (42.9) | 74 (45.7) | 752 (42.7) | |
| Biopsy only | 49 (2.6) | 7 (4.3) | 42 (2.4) | |
| Unknown | 200 (10.4) | 12 (7.4) | 188 (10.7) | |
| Tamoxifen use (excluding after recurrence) | 0.02 | |||
| No | 1039 (54.0) | 105 (64.8) | 934 (53.0) | |
| Yes | 638 (33.1) | 44 (27.2) | 594 (33.7) | |
| Unknown | 248 (12.9) | 13 (8.0) | 235 (13.3) | |
| Mode of detection | 0.41 | |||
| Mammography | 1595 (82.9) | 129 (79.6) | 1466 (83.2) | |
| Symptomatic | 266 (13.8) | 28 (17.3) | 238 (13.5) | |
| Unknown | 64 (3.3) | 5 (3.1) | 59 (3.3) | |
a
P value for Chi-square test comparing women with and without a second breast cancer diagnosis among those with known covariate status