Table 1.
Descriptive summary of the cohorts in which risks were calculated, separately for invasive BC and EOC
| Eligible set for invasive BC analysis | Eligible set for EOC analysis | |||||
|---|---|---|---|---|---|---|
| Overall | BRCA1 a | BRCA2 a | Overall | BRCA1 a | BRCA2 a | |
| Sample, N (%) | 1,895 | 1,042 (55) | 849 (45) | 1,736 | 939 (54) | 793 (46) |
| Mean age at questionnaire (SD) | 45.1 (13.1) | 44.6 (13.1) | 45.6 (13) | 44.2 (13.1) | 43.5 (13) | 45.1 (13.1) |
| Mean follow-up in years (SD) | 7.1 (4.5) | 7.4 (6.6) | 6.6 (4.3) | 7.0 (4.5) | 7.3 (4.7) | 6.6 (4.3) |
| Failures | 23 | 12 | 11 | 2 | 0 | 2 |
| Mean age at failure (SD) | 57.2 (8.8) | 60.5 (9.7) | 53.6 (6.2) | 50.5 (8.0) | — | 50.5 (8.0) |
| Ethnicity (%) | ||||||
| Unknown | 1 (0) | 0 | 1 (0) | 1 (0) | 0 | 1 (0) |
| White | 1,810 (96) | 982 (94) | 824 (97) | 1,658 (95) | 885 (94) | 769 (97) |
| Indian | 5 (0.3) | 4 (0.4) | 1 (0.1) | 5 (0.4) | 4 (0.5) | 1 (0.1) |
| Black-Caribbean | 3 (0.2) | 3 (0.3) | 0 | 3 (0.2) | 3 (0.3) | 0 |
| Ashkenazi Jewish | 47 (2) | 34 (3.4) | 13 (1.8) | 45 (3) | 32 (3.4) | 13 (1.8) |
| Bangladeshi | 1 (0) | 1 (0.1) | 0 | 1 (0) | 1 (0.1) | 0 |
| Pakistani | 3 (0.2) | 2 (0.2) | 1 (0.1) | 3 (0.2) | 2 (0.2) | 1 (0.1) |
| Black other | 5 (0.3) | 5 (0.5) | 0 | 4 (0.3) | 4 (0.5) | 0 |
| Chinese | 1 (0) | 0 | 1 (0.1) | 0 | 0 | 0 |
| Other | 19 (1) | 11 (1.1) | 8 (0.9) | 16 (0.9) | 8 (1) | 8 (1) |
| Number of families (%) | 1,602 | 887 (55) | 711 (45) | 1,488 | 812 (55) | 672 (45) |
| Families by number of noncarriers (%) | ||||||
| 1 | 1,381 (86) | 767 (86) | 610 (86) | 1,300 (87) | 714 (88) | 582 (88) |
| 2 | 179 (11) | 98 (11) | 81 (11) | 152 (11) | 80 (10) | 72 (11) |
| 3 | 25 (2) | 14 (2) | 11 (1.6) | 24 (1.5) | 11 (1.3) | 13 (0.3) |
| 4 | 14 (1) | 6 (0.8) | 8 (1.3) | 9 (0.5) | 5 (0.5) | 4 (0.6) |
| 5 | 1 (0) | 1 (0.1) | 0 | 1 (0) | 1 (0.1) | 0 |
| 6 | 0 | 0 | 0 | 0 | 0 | 0 |
| 7 | 0 | 0 | 0 | 1 (0) | 1 (0.1) | 0 |
| 8 | 1 (0) | 1 (0.1) | 0 | 0 | 0 | 0 |
| 9 | 0 | 0 | 0 | 0 | 0 | 0 |
| 10 | 0 | 0 | 0 | 0 | 0 | 0 |
| 11 | 0 | 0 | 0 | 0 | 0 | 0 |
| 12 | 1 (0) | 0 | 1 (0.1) | 1 (0) | 0 | 1 (0.1) |
BC, breast cancer; EOC, epithelial ovarian cancer.
aIn four individuals family identification number and family mutation were missing. In reference to familial clustering, these individuals were assumed to be independent. No assumptions were made on family mutation; therefore, in the stratified analysis by family mutation, these individuals were not considered.