Table 2.
Risk of Contralateral Breast Cancer in Relation to BRCA1/BRCA2 Mutation Carrier Status Overall and According to Demographic, Familial, and Disease Characteristics
| Characteristic | Cases |
Controls |
Cases and Controls |
|||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| No BRCA1/2 Mutation |
BRCA1-Positive |
BRCA2-Positive |
No BRCA1/2 Mutation |
BRCA1-Positive |
BRCA2-Positive |
BRCA1-Positive |
BRCA2-Positive |
|||||||||
| No. | % | No. | % | No. | % | No. | % | No. | % | No. | % | RR | 95% CI | RR | 95%CI | |
| All women | 597 | 84.7 | 67 | 9.5 | 41 | 5.8 | 1325 | 94.8 | 42 | 3.0 | 31 | 2.2 | 4.5 | 2.8 to 7.1 | 3.4 | 2.0 to 5.8 |
| Age at first breast cancer, years | ||||||||||||||||
| 21-34 | 22 | 45.8 | 22 | 45.8 | 4 | 8.3 | 76 | 84.4 | 9 | 10.0 | 5 | 5.6 | 10.9 | 3.4 to 34.6 | 2.4 | 0.5 to 10.9 |
| 35-44 | 204 | 78.2 | 35 | 13.4 | 22 | 8.4 | 484 | 93.6 | 23 | 4.4 | 10 | 1.9 | 4.0 | 2.1 to 7.5 | 6.3 | 2.6 to 15.4 |
| 45-54 | 371 | 93.7 | 10 | 2.5 | 15 | 3.8 | 765 | 96.7 | 10 | 1.3 | 16 | 2.0 | 2.6 | 1.0 to 7.2 | 2.3 | 1.0 to 5.1 |
| P for heterogeneity | 0.15 | 0.21 | ||||||||||||||
| Interval between first diagnosis and second diagnosis, years (cases)/reference date (controls) | ||||||||||||||||
| < 5 | 340 | 84.0 | 40 | 9.9 | 25 | 6.2 | 764 | 94.7 | 28 | 3.0 | 15 | 2.3 | 4.7 | 2.7 to 8.3 | 4.1 | 2.0 to 8.3 |
| ≥ 5 | 257 | 85.7 | 27 | 9.0 | 16 | 5.3 | 561 | 95.9 | 14 | 2.0 | 16 | 2.1 | 3.9 | 1.7 to 9.4 | 2.7 | 1.2 to 6.1 |
| P for heterogeneity | 0.73 | 0.43 | ||||||||||||||
| Jewish ancestry | ||||||||||||||||
| No | 541 | 84.9 | 59 | 9.3 | 37 | 5.8 | 1,211 | 95.8 | 34 | 2.3 | 27 | 2.0 | 5.1 | 3.0 to 8.4 | 3.8 | 2.1 to 6.6 |
| Yes | 42 | 77.8 | 8 | 14.8 | 4 | 7.4 | 97 | 86.9 | 7 | 6.8 | 4 | 6.3 | 2.3 | 0.6 to 8.9 | 1.6 | 0.3 to 7.6 |
| Unknown | 14 | 100.0 | 0 | 0 | 0 | 0 | 17 | 95.7 | 1 | 4.3 | 0 | 0 | — | — | — | — |
| P for heterogeneity | 0.18 | 0.12 | ||||||||||||||
| First-degree family history* | ||||||||||||||||
| No | 417 | 87.1 | 39 | 8.1 | 23 | 4.8 | 1,065 | 96.0 | 25 | 2.3 | 19 | 1.7 | 6.1 | 3.3 to 11.2 | 3.3 | 1.6 to 6.5 |
| Yes | 180 | 79.6 | 28 | 12.4 | 18 | 8.0 | 260 | 90.0 | 17 | 5.9 | 12 | 4.2 | 2.2 | 1.0 to 4.7 | 2.9 | 1.3 to 6.8 |
| P for heterogeneity | 0.11 | 0.89 | ||||||||||||||
| Race/ethnicity | ||||||||||||||||
| White | 569 | 84.9 | 63 | 9.4 | 38 | 5.7 | 1,267 | 94.9 | 40 | 3.0 | 28 | 2.1 | 4.3 | 2.7 to 7.0 | 3.4 | 2.0 to 6.0 |
| Non-Hispanic | 552 | 85.4 | 59 | 9.1 | 35 | 5.4 | 1,223 | 95.0 | 38 | 3.0 | 26 | 2.0 | 4.1 | 2.5 to 6.8 | 3.2 | 1.8 to 5.8 |
| Hispanic | 17 | 70.8 | 4 | 16.7 | 3 | 12.5 | 44 | 91.7 | 2 | 4.2 | 2 | 4.2 | 10.4 | 1.1 to 95.3 | 9.3 | 0.7 to 122.7 |
| Black | 18 | 85.7 | 2 | 9.5 | 1 | 4.8 | 35 | 89.7 | 1 | 2.6 | 3 | 7.7 | 7.0 | 0.5 to 98.2 | 1.2 | 0.1 to 12.0 |
| Asian or other | 10 | 71.4 | 2 | 14.3 | 2 | 14.3 | 23 | 95.8 | 1 | 4.2 | 0 | 0 | 6.5 | 0.5 to 80.8 | — | — |
| P for heterogeneity | 0.82 | 0.26 | ||||||||||||||
NOTE. Rate ratios (RRs) and CIs account for counter-matching, are adjusted for age at first diagnosis, and compare the risk of contralateral breast cancer in carriers versus noncarriers of mutations in either gene, overall and within each demographic, familial, or disease characteristic subgroup. Proportions are weighted for the counter-matching with the exception of factors contributing to the study matching schema (age, race/ethnicity, and center).
*
First-degree family history includes mothers and sisters with breast cancer.