Age-specific prevalence of BRCA1/2 mutation carriers among breast cancer cases as observed in van den Broek11 and number of BIA-ALCL cases with breast cancer by age
| . | Age at breast cancer diagnosis, y . | ||||
|---|---|---|---|---|---|
| <35 . | 35-39 . | 40-44 . | 45-49 . | >50* . | |
| Expected prevalence of BRCA1/2 mutations in breast cancer patients (%)11 | 10.7 | 6.1 | 4.3 | 2.4 | 2.4* |
| Observed BIA-ALCL patients per age category (n) | 1 | 2 | 1 | 3 | 8 |
| . | Age at breast cancer diagnosis, y . | ||||
|---|---|---|---|---|---|
| <35 . | 35-39 . | 40-44 . | 45-49 . | >50* . | |
| Expected prevalence of BRCA1/2 mutations in breast cancer patients (%)11 | 10.7 | 6.1 | 4.3 | 2.4 | 2.4* |
| Observed BIA-ALCL patients per age category (n) | 1 | 2 | 1 | 3 | 8 |
The prevalence of BRCA1/2 mutation carriers among BIA-ALCL cases with breast cancer was estimated as the geometric mean of age-specific BRCA1/2 prevalences among BIA-ALCL cases multiplied by 100/61 to correct for the incomplete mutation testing panel.11
Calculation: (0.1069 × 0.06122 × 0.0432 × 0.02411)(1/15) = 0.0312. After correction: 0.0312 × 100/61 = 5.1 (95% CI, 4.6-5.7).
Prevalence for age 45-49 y was also used for the group aged >50 y to best approximate prevalence because specific data for this age group are unknown.11