Contralateral breast cancer in BRCA1 and BRCA2 mutation carriers.
OBJECTIVE
To estimate the risk of contralateral breast cancer in BRCA1 and BRCA2 carriers after diagnosis and to determine which factors are predictive of the risk of a second primary breast cancer.


METHODS
Patients included 491 women with stage I or stage II breast cancer, for whom a BRCA1 or BRCA2 mutation had been identified in the family. Patients were followed from the initial diagnosis of cancer until contralateral mastectomy, contralateral breast cancer, death, or last follow-up.


RESULTS
The actuarial risk of contralateral breast cancer was 29.5% at 10 years. Factors that were predictive of a reduced risk were the presence of a BRCA2 mutation (v BRCA1 mutation; hazard ratio [HR], 0.73; 95% CI, 0.47 to 1.15); age 50 years or older at first diagnosis (v <or= 49 years; HR, 0.63; 95% CI, 0.36 to 1.10); use of tamoxifen (HR, 0.59; 95% CI, 0.35 to 1.01); and history of oophorectomy (HR, 0.44; 95% CI, 0.21 to 0.91). The effect of oophorectomy was particularly strong in women first diagnosed prior to age 49 years (HR, 0.24; 95% CI, 0.07 to 0.77). For women who did not have an oophorectomy or take tamoxifen, the 10-year risk of contralateral cancer was 43.4% for BRCA1 carriers and 34.6% for BRCA2 carriers.


CONCLUSIONS
The risk of contralateral breast cancer in women with a BRCA mutation is approximately 40% at 10 years, and is reduced in women who take tamoxifen or who undergo an oophorectomy.
Metcalfe
Kelly
K
Centre for Research on Women' s Health, Women's College Hospital, Toronto, Ontario, Canada.
Lynch
Henry T
HT
Ghadirian
Parviz
P
Tung
Nadine
N
Olivotto
Ivo
I
Warner
Ellen
E
Olopade
Olufunmilayo I
OI
Eisen
Andrea
A
Weber
Barbara
B
McLennan
Jane
J
Sun
Ping
P
Foulkes
William D
WD
Narod
Steven A
SA
D000328:Adult; D017668:Age of Onset; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology*; D005260:Female; D019398:Genes, BRCA1; D024522:Genes, BRCA2; D020022:Genetic Predisposition to Disease; D006801:Humans; D008875:Middle Aged; D009154:Mutation; D016609:Neoplasms, Second Primary / Q000453:epidemiology*; D010052:Ovariectomy; D011446:Prospective Studies; D012306:Risk; D013629:Tamoxifen / Q000627:therapeutic use
D013629:Tamoxifen