Variation in Mutation Spectrum Partly Explains Regional Differences in the Breast Cancer Risk of Female BRCA Mutation Carriers in the Netherlands

Janet R. Vos*, Natalia Teixeira, Dorina M van der Kolk, Marian J E Mourits, Matti A Rookus, Flora E van Leeuwen, Margriet Collée, Christi J van Asperen, Arjen R Mensenkamp, Margreet G E M Ausems, Theo A M van Os, Hanne E J Meijers-Heijboer, Encarna B Gómez-Garcia, Hans F Vasen, Richard M Brohet, Annemarie van der Hout, Marijke Jansen -van der Weide, Jan C Oosterwijk, Geertruida H de Bock, Hereditary Breast and Ovarian Cancer Research Group Netherlands

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

7 Citations (Scopus)


Background: We aimed to quantify previously observed relatively high cancer risks in BRCA2 mutation carriers (BRCA2 carriers) older than 60 in the Northern Netherlands, and to analyze whether these could be explained by mutation spectrum or population background risk.

Methods: This consecutive cohort study included all known pathogenic BRCA1/2 carriers in the Northern Netherlands (N = 1,050). Carrier and general reference populations were: BRCA1/2 carriers in the rest of the Netherlands (N = 2,013) and the general population in both regions. Regional differences were assessed with HRs and ORs. HRs were adjusted for birth year and mutation spectrum.

Results: All BRCA1 carriers and BRCA2 carriers younger than 60 had a significantly lower breast cancer risk in the Northern Netherlands; HRs were 0.66 and 0.64, respectively. Above age 60, the breast cancer risk in BRCA2 carriers in the Northern Netherlands was higher than in the rest of the Netherlands [HR, 3.99; 95% confidence interval (CI), 1.11-14.35]. Adjustment for mutational spectrum changed the HRs for BRCA1, BRCA2 = 60 years by -3%, +32%, and +11% to 0.75, 0.50, and 2.61, respectively. There was no difference in background breast cancer incidence between the two regions (OR, 1.03; 95% CI, 0.97-1.09).

Conclusions: Differences in mutation spectrum only partly explain the regional differences in breast cancer risk in BRCA2 carriers, and for an even smaller part in BRCA1 carriers.

Impact: The increased risk in BRCA2 carriers older than 60 may warrant extension of intensive breast screening beyond age 60. (C)2014 AACR.

Original languageEnglish
Pages (from-to)2482-2491
Number of pages10
Issue number11
Publication statusPublished - Nov-2014



Cite this