title: Risk of ipsilateral breast cancer in BRCA1 and BRCA2 mutation carriers.
abstract: Women with a BRCA1 or BRCA2 mutation have an elevated risk of breast cancer and of contralateral breast cancer. In this study, we estimate the risk of non-synchronous ipsilateral breast cancer after a diagnosis of breast cancer in BRCA carriers and evaluate the effects of various treatments on this risk. Patients were 396 women with stage I or stage II breast cancer with an intact ipsilateral breast and for whom a BRCA1 or BRCA2 mutation had been identified in the family. Patients were followed from the initial diagnosis of cancer until the first of ipsilateral mastectomy, ipsilateral breast cancer, death or last follow-up. The 5-year actuarial risk of ipsilateral breast cancer was 5.8% (95% CI 3.2-8.4%) and the 10-year risk was 12.9% (95% CI 8.7-17.1%). Subjects who received chemotherapy had a significantly lower risk of ipsilateral breast cancer compared to those who did not receive chemotherapy (RR 0.45; 95% CI 0.24-0.84; P = 0.01). Radiotherapy was associated with a reduced risk of ipsilateral breast cancer (RR 0.28; 95% CI 0.12-0.63; P = 0.002). Oophorectomy was associated with a significant reduction in the risk of ipsilateral breast cancer (RR 0.33; 95% CI; 0.13-0.81; P = 0.02). On average, following a diagnosis of breast cancer, the annual risk of ipsilateral breast cancer risk in BRCA mutation carriers is 1.2% per year. For women treated with chemotherapy, radiation therapy or oophorectomy the risk is low, compared to women who did not receive any of these treatments.
authors.affiliation: Lawrence S. Bloomberg Faculty of Nursing, University of Toronto, Toronto, Canada.
authors.forename: Kelly
authors.initials: K
authors.lastname: Metcalfe
authors.forename: Henry T
authors.initials: HT
authors.lastname: Lynch
authors.forename: Parviz
authors.initials: P
authors.lastname: Ghadirian
authors.forename: Nadine
authors.initials: N
authors.lastname: Tung
authors.forename: Charmaine
authors.initials: C
authors.lastname: Kim-Sing
authors.forename: Olufunmilayo I
authors.initials: OI
authors.lastname: Olopade
authors.forename: Susan
authors.initials: S
authors.lastname: Domchek
authors.forename: Andrea
authors.initials: A
authors.lastname: Eisen
authors.forename: William D
authors.initials: WD
authors.lastname: Foulkes
authors.forename: Barry
authors.initials: B
authors.lastname: Rosen
authors.forename: Danny
authors.initials: D
authors.lastname: Vesprini
authors.forename: Ping
authors.initials: P
authors.lastname: Sun
authors.forename: Steven A
authors.initials: SA
authors.lastname: Narod
mesh_terms: D000328:Adult; D000368:Aged; D019313:BRCA1 Protein / Q000235:genetics*; D024682:BRCA2 Protein / Q000235:genetics*; D001943:Breast Neoplasms / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D006579:Heterozygote; D006801:Humans; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D009656:North America / Q000453:epidemiology; D011379:Prognosis; D012307:Risk Factors; D055815:Young Adult
chemical_list: D019313:BRCA1 Protein; D024682:BRCA2 Protein