Table 4. Risk of specific cancers for parents and siblings of index cases.
| Observed | Expected | SIR (95% CI) | |
|---|---|---|---|
| Ovarian cancer (mothers and sisters) | |||
| Index case: BRCA1 positive | 2 | 0.16 | 12.38 (3.10–49.51) |
| Index case: BRCA2 positive | 0 | 0.11 | — |
| Index case: negative | 5 | 2.45 | 2.04 (0.85–4.91) |
| Index case: unknown | 1 | 0.54 | 1.87 (0.26–13.26) |
| Prostate cancer (fathers and brothers) | |||
| Index case: BRCA1 positive | 0 | 0.13 | — |
| Index case: BRCA2 positive | 2 | 0.11 | 18.55 (4.64–74.17) |
| Index case: negative | 7 | 1.33 | 5.25 (2.50–11.01) |
| Index case: unknown | 3 | 0.26 | 11.51 (3.71–35.69) |
| Colorectal cancer (parents and siblings) | |||
| Index case: BRCA1 positive | 1 | 0.74 | 1.35 (0.19–9.57) |
| Index case: BRCA2 positive | 1 | 0.49 | 2.03 (0.29–14.41) |
| Index case: negative | 8 | 10.77 | 0.74 (0.37–1.49) |
| Index case: unknown | 2 | 2.09 | 0.96 (0.24–3.83) |
| Brain cancer (parents and siblings) | |||
| Index case: BRCA1 positive | 0 | 0.11 | — |
| Index case: BRCA2 positive | 0 | 0.07 | — |
| Index case: negative | 5 | 1.61 | 3.10 (1.29–7.45) |
| Index case: unknown | 1 | 0.36 | 2.76 (0.39–19.60) |
| Cervical cancer (mothers and sisters) | |||
| Index case: BRCA1 positive | 0 | 0.40 | — |
| Index case: BRCA2 positive | 0 | 0.30 | — |
| Index case: negative | 9 | 6.18 | 1.46 (0.76–2.80) |
| Index case: unknown | 0 | 1.32 | — |
| Lung cancer (parents and siblings) | |||
| Index case: BRCA1 positive | 1 | 0.17 | 5.95 (0.84–42.21) |
| Index case: BRCA2 positive | 1 | 0.11 | 9.18 (1.29–65.20) |
| Index case: negative | 16 | 2.07 | 7.73 (4.74–12.62) |
| Index case: unknown | 2 | 0.50 | 4.00 (1.00–16.00) |
| Stomach cancer (parents and siblings) | |||
| Index case: BRCA1 positive | 0 | 0.60 | — |
| Index case: BRCA2 positive | 0 | 0.45 | — |
| Index case: negative | 8 | 7.77 | 1.03 (0.52–2.00) |
| Index case: unknown | 0 | 1.61 | |
| Urinary cancers (parents and siblings) | |||
| Index case: BRCA1 positive | 0 | 0.09 | — |
| Index case: BRCA2 positive | 0 | 0.06 | — |
| Index case: negative | 5 | 1.15 | 4.35 (1.81–10.46) |
| Index case: unknown | 2 | 0.28 | 7.23 (1.81–28.90) |
Abbreviations: CI=confidence interval; SIR=standardised incidence ratio.