Table 1.

Prediagnosis subject characteristics and distribution of second breast cancer diagnoses; N (%): WISC DCIS cohort, 1997–2010

TotalSecond breast cancer diagnosisNo second breast cancer diagnosis
N = 1,925N = 162N = 1,763Pa
Age at diagnosis, y0.13
 20–44238 (12.4)21 (13.0)217 (12.3)
 45–54684 (35.5)66 (40.7)618 (35.1)
 55–64585 (30.4)36 (22.2)549 (31.1)
 65–74418 (21.7)39 (24.1)379 (21.5)
Menopausal status0.01
 Premenopausal617 (32.1)70 (43.2)547 (31.0)
 Postmenopausal1,147 (59.6)82 (50.6)1,065 (60.4)
 Unknown161 (8.4)10 (6.2)151 (8.6)
First degree family history of breast cancer0.85
 No1,380 (71.7)114 (70.4)1,266 (71.8)
 Yes430 (22.3)39 (24.1)391 (22.2)
 Unknown115 (6.0)9 (5.6)106 (6.0)
Postmenopausal hormone use<0.01
 Never1,287 (66.9)129 (79.6)1,158 (65.7)
 Ever587 (30.5)30 (18.5)557 (31.6)
 Unknown51 (2.7)3 (1.9)48 (2.7)
Parity0.55
 No births270 (14.0)27 (16.7)243 (13.8)
 One birth197 (10.2)13 (8.0)184 (10.4)
 Two births594 (30.9)53 (32.7)541 (30.7)
 3+ births839 (43.6)67 (41.4)772 (43.8)
 Unknown25 (1.3)2 (1.2)23 (1.3)
Education0.37
 < High school diploma93 (4.8)5 (3.1)88 (5.0)
 High school diploma736 (38.2)64 (39.5)672 (38.1)
 Some college514 (26.7)47 (29.0)467 (26.5)
 College degree552 (28.7)46 (28.4)506 (28.7)
 Unknown30 (1.6)030 (1.7)
Smoking status0.38
 Never1,053 (54.7)88 (54.3)965 (54.7)
 Former557 (28.9)54 (33.3)503 (28.5)
 Current288 (15.0)20 (12.4)268 (15.2)
 Unknown27 (1.4)027 (1.5)
Surgical treatment<0.01
 Ipsilateral mastectomy593 (30.8)41 (25.3)552 (31.3)
 Bilateral mastectomy81 (4.2)081 (4.6)
 BCS without radiation176 (9.1)28 (17.3)148 (8.4)
 BCS with radiation826 (42.9)74 (45.7)752 (42.7)
 Biopsy only49 (2.6)7 (4.3)42 (2.4)
 Unknown200 (10.4)12 (7.4)188 (10.7)
Tamoxifen use (excluding after recurrence)0.02
 No1,039 (54.0)105 (64.8)934 (53.0)
 Yes638 (33.1)44 (27.2)594 (33.7)
 Unknown248 (12.9)13 (8.0)235 (13.3)
Mode of detection0.41
 Mammography1,595 (82.9)129 (79.6)1,466 (83.2)
 Symptomatic266 (13.8)28 (17.3)238 (13.5)
 Unknown64 (3.3)5 (3.1)59 (3.3)
  • aP for χ2 test comparing women with and without a second breast cancer diagnosis among those with known covariate status.