Population-based study of the risk of second primary contralateral breast cancer associated with carrying a mutation in BRCA1 or BRCA2
Kathleen E Malone, Colin B Begg, Robert W Haile, Ake Borg, Patrick Concannon, Lina Tellhed, Shanyan Xue, Sharon Teraoka, Leslie Bernstein, Marinela Capanu, Anne S Reiner, Elyn R Riedel, Duncan C Thomas, Lene Mellemkjaer, Charles F Lynch, John D Boice Jr, Hoda Anton-Culver, Jonine L Bernstein, Kathleen E Malone, Colin B Begg, Robert W Haile, Ake Borg, Patrick Concannon, Lina Tellhed, Shanyan Xue, Sharon Teraoka, Leslie Bernstein, Marinela Capanu, Anne S Reiner, Elyn R Riedel, Duncan C Thomas, Lene Mellemkjaer, Charles F Lynch, John D Boice Jr, Hoda Anton-Culver, Jonine L Bernstein
Abstract
Purpose: Women with breast cancer diagnosed early in life comprise a substantial portion of those tested for BRCA1/BRCA2 mutations; however, little information is available on the subsequent risks of contralateral breast cancer in mutation carriers. This study assessed the risk of subsequent contralateral breast cancer associated with carrying a BRCA1 or BRCA2 mutation.
Patients and methods: In this nested case-control study, patients with contralateral breast cancer diagnosed 1 year or more after a first primary breast cancer (n = 705) and controls with unilateral breast cancer (n = 1,398) were ascertained from an underlying population-based cohort of 52,536 women diagnosed with a first invasive breast cancer before age 55 years. Interviews and medical record reviews were used to collect risk factor and treatment histories. All women were tested for BRCA1/BRCA2 mutations. Relative (rate ratios) and absolute (5- and 10-year cumulative) risks of developing contralateral breast cancer following a first invasive breast cancer were computed.
Results: Compared with noncarriers, BRCA1 and BRCA2 mutation carriers had 4.5-fold (95% CI, 2.8- to 7.1-fold) and 3.4-fold (95% CI, 2.0- to 5.8-fold) increased risks of contralateral breast cancer, respectively. The relative risk of contralateral breast cancer for BRCA1 mutation carriers increased as age of first diagnosis decreased. Age-specific cumulative risks are provided for clinical guidance.
Conclusion: The risks of subsequent contralateral breast cancer are substantial for women who carry a BRCA1/BRCA2 mutation. These findings have important clinical relevance regarding the assessment of BRCA1/BRCA2 status in patients with breast cancer and the counseling and clinical management of patients found to carry a mutation.
Conflict of interest statement
Authors' disclosures of potential conflicts of interest and author contributions are found at the end of this article.
Source: PubMed