Table 2. Risk of asynchronous contralateral breast cancer in relation to treatment for first primary breast cancer according to BRCA1/2 mutation carrier status.
| Non-carriers | BRCA1 | BRCA2 | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Treatment for first Breast Cancer |
Bilateral | Unilateral | Bilateral | Unilateral | Bilateral | Unilateral | ||||||||
| n (%) | n (%)1 | RR2 | 95% CI | n (%) | n (%)1 | RR2 | 95%CI | n (%) | n (%)1 | RR2 | 95% CI | p-value3 | ||
| Chemotherapy | ||||||||||||||
| No | 343 (57.5) | 611 (43.6) | 1.0 | (ref) | 20 (29.9) | 5 (21.4) | 1.0 | (ref) | 21 (51.2) | 12 (31.3) | 1.0 | (ref) | 0.34 | |
| Yes | 254 (42.5) | 714 (56.4) | 0.6 | 0.5-0.7 | 47 (70.1) | 37 (78.6) | 0.5 | 0.1-1.6 | 20 (48.8) | 19 (68.7) | 0.3 | 0.1-1.0* | ||
| Tamoxifen | ||||||||||||||
| No | 434 (72.7) | 899 (68.7) | 1.0 | (ref) | 65 (97.0) | 35 (90.7) | 1.0 | (ref) | 29 (70.7) | 25 (82.2) | 1.0 | (ref) | 0.72 | |
| Yes | 163 (27.3) | 424 (31.0) | 0.7 | 0.6-1.0* | 2 (3.0) | 7 (9.3) | 0.2 | 0.0-1.3 | 12 (29.3) | 6 (17.8) | 0.9 | 0.5-6.9 | ||
1
Weighted percentages
2
Rate Ratios (RR) and 95% confidence intervals (CI) are adjusted for age at first diagnosis.
3
Testing for heterogeneity between non-carriers, BRCA1, and BRCA2 mutation carriers
*
Due to rounding, p-value < 0.05