Table 4 Rates of cancer in mutation-negative relatives in BRCA1/2 families.
From: Evidence That BRCA1- or BRCA2-Associated Cancers Are Not Inevitable
Reference | Number of patients mutation negative | Relationship to mutation carrier | Length of follow-up | Breast and other cancer risk (CI) and comments |
|---|---|---|---|---|
1,492 | FDR | Mean 6.1 years, followed up to age 75 | Standardized incidence ratio (SIR) 4.3 Ovarian and colon cancer risks were slightly below normal | |
104 | FDR/SDR | Median 8 years | SIR 2.9 (1.0–8.6) | |
11,378 | FDR | NA | Relative risk (RR) 0.39 (0.04–3.8); substantial risk heterogeneity High-risk women account for only 3.4% of the female populations in three countries studied, but 32% of all breast cancer cases; uses a constant value for risk of carriers; assumes one additional latent gene to account for all risk | |
184 | FDR | NA | SIR 5.0 | |
395 | FDR/SDR/TDR | Entry at 31.3 years followed for average of 17.7 years to age 48; third-degree relative to age 41 | For FDR, SIR 1.33 (0.49–2.91); all RR = 0.75 (0.34–1.41); assumptions about oophorectomy | |
130.5 | FDR | Diagnosis before age 50 | Odds ratio (OR) 2 | |
442 | FDR/SDR | Median 6.1 years | SIR 1.29 (0.58–2.88); excluded 400 women with a prior cancer diagnosis | |
375 | FDR/SDR mostly | Median age 44 mean follow up 4.9 years | SIR 2.3 (0.57–9.19) for in situ breast cancer | |
3,742 | FDR | NA | OR 1.6 (1.2–2.1) |