Table 1.
Patient and tumor characteristics
| Characteristic | BC-P cases N = 65 | Controls for BC-P cases N = 135 | BC-PP cases N = 75 | Controls for BC-PP cases N = 145 | P value for comparison of BC-P cases to their controlsb | P value for comparison of BC-PP cases to their controlsb | P value for comparison of BC-P cases to BC-PP casesb |
|---|---|---|---|---|---|---|---|
| Mean age at diagnosis in years (SD) | 34.5 (5.0) | 36.7 (5.3) | 34.7 (3.8) | 37.2 (4.7) | 0.007 | < 0.001 | 0.83 |
| Treatment location (N, %) | |||||||
| Johns Hopkins | 9 (14%)a | 25 (19%) | 7 (9%) | 35 (24%) | < 0.001 | < 0.001 | 0.65 |
| Another institution | 30 (46%) | 24 (18%) | 34 (45%) | 25 (17%) | |||
| Both | 26 (40%) | 82 (63%) | 34 (45%) | 84 (58%) | |||
| Year of diagnosis (N, %) | |||||||
| 1985–1989 | 1 (2%) | 4 (3%) | 1 (1%) | 3 (2%) | 0.83 | 0.28 | 0.99 |
| 1990–1994 | 2 (3%) | 7 (5%) | 3 (4%) | 13 (9%) | |||
| 1995–1999 | 9 (14%) | 17 (13%) | 9 (12%) | 11 (8%) | |||
| 2000–2004 | 26 (40%) | 49 (37%) | 3 (40%) | 47 (33%) | |||
| 2005–2009 | 13 (20%) | 20 (15%) | 13 (17%) | 40 (28%) | |||
| 2010–2014 | 14 (22%) | 36 (27%) | 19 (25%) | 30 (21%) | |||
| Race (N, %) | |||||||
| White | 42 (67%) | 97 (73%) | 59 (79%) | 97 (67%) | 0.52 | 0.43 | 0.35 |
| Black | 15 (24%) | 28 (21%) | 11 (15%) | 34 (24%) | |||
| Asian | 1 (2%) | 3 (2%) | 2 (3%) | 3 (2%) | |||
| Other | 5 (8%) | 4 (3%) | 3 (4%) | 9 (6%) | |||
| Unknown | 0 (0%) | 1 (1%) | 0 (0%) | 1 (1%) | |||
| Stage (N, %) | |||||||
| 0 (DCIS) | 3 (5%) | 4 (3%) | 3 (4%) | 4 (3%) | 0.81 | 0.68 | 0.30 |
| I | 10 (15%) | 27 (20%) | 11 (15%) | 34 (23%) | |||
| II | 26 (40%) | 53 (39%) | 25 (33%) | 46 (32%) | |||
| III | 14 (22%) | 33 (24%) | 16 (21%) | 33 (23%) | |||
| IV | 7 (11%) | 10 (7%) | 20 (17%) | 25 (17%) | |||
| Unknown | 5 (8%) | 8 (6%) | 5 (7%) | 3 (2%) | |||
| Grade (N, %) | |||||||
| 1 | 1 (2%) | 11 (9%) | 2(3%) | 8 (6%) | 0.017 | 0.008 | 0.60 |
| 2 | 14 (22%) | 41 (34%) | 11 (16%) | 46 (34%) | |||
| 3 | 49 (77%) | 69 (57%) | 57 (81%) | 81 (60%) | |||
| ER-positive (N, %) | 29 (51%) | 94 (72%) | 42 (63%) | 111 (80%) | 0.004 | 0.006 | 0.19 |
| HER2-positive (N, %) | 13 (25%) | 27 (27%) | 19 (33%) | 25 (23%) | 0.77 | 0.14 | 0.31 |
| Family history of breast or ovarian cancer (N, %) | 28 (47%) | 54 (46%) | 32 (47%) | 60 (44%) | 0.91 | 0.69 | 0.97 |
| Age at Menarche in years (N, %) | |||||||
| ≤10 | 2 (8%) | 4 (6%) | 4 (9%) | 5 (6%) | 0.25 | 0.39 | 0.68 |
| 11 | 2 (8%) | 6 (9%) | 8 (19%) | 14 (18%) | |||
| 12 | 10 (38%) | 13 (20%) | 16 (37%) | 19 (24%) | |||
| 13 | 7 (27%) | 14 (22%) | 7 (16%) | 29 (23%) | |||
| ≥14 | 5 (19%) | 27 (42%) | 8 (19%) | 18 (23%) | |||
| Parity at diagnosis (N, %) | |||||||
| 0 | 21 (34%) | 41 (33%) | 0 (0%) | 44 (33%) | 0.51 | < 0.001 | < 0.001 |
| 1–3 | 38 (61%) | 79 (63%) | 65 (92%) | 80 (60%) | |||
| 4–5 | 1 (2%) | 5 (4%) | 5 (7%) | 6 (4%) | |||
| ≥6 | 2 (3%) | 1 (1%) | 1 (1%) | 4 (3%) | |||
| Mean duration of follow-up in months (SD) | 50.9 (51.9) | 78.4 (66.0) | 55.8 (55.6) | 72.8 (61.1) | 0.002 | 0.04 | 0.59 |
a
All percentages based on non-missing values
b
P values for t tests and Chi-squared tests performed on non-missing proportions