Table 2. Standardised incidence ratios (SIRs) for breast cancer in 712 unaffected female blood relatives of 75 patients with ataxia telangiectasia (AT) by age at diagnosis.
|
Age at breast cancer diagnosis
|
||||||||
|---|---|---|---|---|---|---|---|---|
|
<55 years
|
⩾55 years
|
|||||||
| Female relative | Obs | Exp | SIR | 95% CI | Obs | Exp | SIR | 95% CI |
| Total | 21 | 7.19 | 2.9 | 1.8–4.5 | 13 | 12.32 | 1.1 | 0.6–1.8 |
| Familial relation | ||||||||
| Mother | 7 | 0.86 | 8.1 | 3.3–17 | 1 | 0.34 | 3.0 | 0.0–16 |
| Grandmother and grandmother's sister | 9 | 3.07 | 2.9 | 1.3–5.6 | 6 | 7.23 | 0.8 | 0.3–1.8 |
| Great grandmother | 3 | 0.57 | 5.3 | 1.1–15 | 5 | 3.32 | 1.5 | 0.5–3.5 |
| Cousin and aunt | 2 | 2.63 | 0.8 | 0.1–2.8 | 1 | 1.43 | 0.7 | 0.0–3.9 |
| Mutation carrier probabilitya | ||||||||
| 1 | 7 | 0.98 | 7.1 | 2.9–15 | 1 | 0.83 | 1.2 | 0.0–6.7 |
| 0.67; 0.50 | 5 | 3.55 | 1.4 | 0.5–3.3 | 5 | 4.51 | 1.1 | 0.4–2.6 |
| 0.25 | 8 | 2.14 | 3.7 | 1.6–7.4 | 6 | 5.18 | 1.2 | 0.4–2.5 |
| Background | 1 | 0.52 | 1.9 | 0.0–11 | 1 | 1.80 | 0.6 | 0.0–3.1 |
Obs=observed cancers; Exp=expected cancers; CI=confidence interval.
a
0.005–0.01, as in the background population.