Table 1. Overview of women (n=1951) and their BCs (n=184)a.
|
All ages |
Age ⩽40 years |
Age 41–50 years |
Age over 50 years |
|||||
|---|---|---|---|---|---|---|---|---|
| BRCA1 | BRCA2 | BRCA1 | BRCA2 | BRCA1 | BRCA2 | BRCA1 | BRCA2 | |
| Women (N) | 1219 | 732 | 605 | 301 | 482 | 308 | 310 | 228 |
| Follow-up time (woman-years) | 3840 | 2245 | 1691 | 749 | 1216 | 812 | 895 | 673 |
| BC (N) | 112 | 72 | 46 | 18 | 38 | 37 | 28 | 17 |
| BC risk ((95% CI) | 29.2 (24–35.1) | 32.1 (25.1–.40.4) | 27.2 (19.9–36.3) | 24 (14.2–38) | 31.3 (22.1–42.9) | 45.6 (32.1–62.8) | 31.3 (20.8–45.2) | 25.3 (14.7–40.4) |
| DCISb | 15 (13.4%) | 22 (30.6%) | 9 (19.6%) | 3 (16.7%) | 3 (7.9%) | 13 (35.1%) | 3 (10.7%) | 6 (35.3%) |
| Invasive cancersc | 97 (86.6%) | 50 (69.4%) | 37 (80.4%) | 15 (83.3%) | 35 (92.1%) | 24 (64.9%) | 25 (89.3%) | 11 (64.7%) |
| Invasive <1 cm | 26 (26.8%) | 17 (34.0%) | 8 (21.6%) | 2 (13.3%) | 10 (28.6%) | 11 (45.8%) | 8 (32.0%) | 4 (36.4%) |
| Invasive 1–2 cm | 35 (36.1%) | 12 (24.0%) | 13 (35.1%) | 5 (33.3%) | 8 (22.9%) | 3 (12.5%) | 14 (56.0%) | 4 (36.4%) |
| Grade 1 | 7 (7.2%) | 5 (10.0%) | 1 (2.7%) | 0 (−) | 4 (11.4%) | 3 (12.5%) | 2 (8.0%) | 2 (18.2%) |
| Early-stage tumour (DCIS or invasive <1 cm) | 41(36.6%) | 39 (54.2%) | 17 (37.0%) | 5 (27.8%) | 13 (34.2%) | 24 (64.9%) | 11 (39.3%) | 10 (58.8%) |
Abbreviations: BC=breast cancer; DCIS=ductal carcinoma in situ.
BC risk was expressed per 1000 woman-years of follow-up.
a
Stratified by age at screening and for BRCA1 or BRCA2 mutation status
b
P=0.0095 comparing DCIS rate between BRCA1 and BRCA2 mutation carriers at the age 41–50 years, and for all ages, comparing DCIS rate between BRCA1 and BRCA2 mutation carriers, P=0.0077.
c
Nine cases with missing histological subtype were considered as invasive BCs.