Table 1.

Clinical characteristics of BRCA1/2 carriers, excluding index cases, in the Northern Netherlands (study population) and in the rest of the Netherlands (reference population)

BRCA1 carriersBRCA2 carriers
Northern NetherlandsRest of the NetherlandsNorthern NetherlandsRest of the Netherlands
CharacteristicsN = 467N = 1,091PN = 269N = 305P
Age at last follow-up, mean (SD)47.6 (13.8)42.1 (11.9)<0.00148.2 (14.1)44.9 (11.9)0.003
Primary breast cancer
N (%)157 (34%)373 (34%)0.86174 (28%)95 (31%)0.359
 Age, mean (SD)43.6 (9.9)41.2 (9.0)0.00649.1 (9.8)44.5 (8.1)0.001
 At age 60, N (% of all breast cancers)13 (8%)12 (3%)0.02213 (18%)3 (3%)0.002
Ovarian cancer
N (%)75 (16%)80 (7%)<0.00116 (6%)21 (7%)0.735
 Age, mean (SD)51.7 (10.0)51.6 (9.7)0.97256.1 (9.6)55.1 (11.5)0.799
RRM
N (%)86 (19%)173 (16%)0.20736 (14%)38 (13%)0.709
 Age, mean (SD)40.9 (9.7)39.9 (10.0)0.48641.6 (8.8)41.0 (7.3)0.740
RRSO
N (%)146 (31%)227 (21%)<0.00183 (31%)49 (16%)<0.001
 Age, mean (SD)44.1 (8.5)44.2 (8.4)0.79147.7 (9.6)46.0 (8.8)0.326
Presymptomatic BC at DNA testa
N (% of all tests)252 (78%)519 (73%)0.093180 (83%)113 (75%)0.114
 Older than 60, N (% of presymptomatic test)23 (9%)55 (11%)0.52819 (10%)15 (13%)0.574
 Age, mean (SD)40.3 (13.0)40.6 (14.0)0.79242.2 (13.6)43.1 (14.1)0.582

Abbreviation: BC, breast cancer.

  • aData on the demographic details of genetic testing were available for 74% of the populations.