Tamoxifen and contralateral breast cancer in BRCA1 and BRCA2 carriers: an update.
Women with a mutation in BRCA1 or BRCA2 face a lifetime risk of breast cancer of approximately 80%, and following the first diagnosis the 10-year risk of contralateral breast cancer is approximately 30%. It has been shown that both tamoxifen and oophorectomy prevent contralateral breast cancer, but it is not clear whether there is a benefit in giving tamoxifen to women who have previously undergone an oophorectomy. Furthermore, the relative degree of protection in BRCA1 and BRCA2 carriers has not been well evaluated. We studied 285 women with bilateral breast cancer and a BRCA1 or BRCA2 mutation, and 751 control women with unilateral breast cancer and a BRCA1 or BRCA2 mutation in a matched case-control study. Control women were of similar age and had a similar age of diagnosis of breast cancer and had been followed for as long as the case for a second primary breast cancer. The history of tamoxifen use for treating the first breast cancer was compared between bilateral and unilateral cases. The multivariate odds ratio for contralateral breast cancer associated with tamoxifen use was 0.50 for carriers of BRCA1 mutations (95% CI, 0.30-0.85) and was 0.42 for carriers of BRCA2 mutations (95% CI, 0.17-1.02). The protective effect of tamoxifen was not seen among women who had undergone an oophorectomy (OR = 0.83; 95%CI, 0.24-2.89) but this subgroup was small. In contrast, a strong protective effect of tamoxifen was apparent among women who were premenopausal or who had undergone natural menopause (OR = 0.44; 95% CI, 0.27-0.65).
Gronwald
Jacek
J
Hereditary Cancer Center, Department of Genetics and Pathology, Pomeranian Medical Academy, Szczecin, Poland.
Tung
Nadine
N
Foulkes
William D
WD
Offit
Kenneth
K
Gershoni
Ruth
R
Daly
Mary
M
Kim-Sing
Charmaine
C
Olsson
Hakan
H
Ainsworth
Peter
P
Eisen
Andrea
A
Saal
Howard
H
Friedman
Eitan
E
Olopade
Olufunmilayo
O
Osborne
Michael
M
Weitzel
Jeffrey
J
Lynch
Henry
H
Ghadirian
Parviz
P
Lubinski
Jan
J
Sun
Ping
P
Narod
Steven A
SA
D000328:Adult; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000209:etiology / Q000235:genetics* / Q000517:prevention & control*; D016022:Case-Control Studies; D004252:DNA Mutational Analysis; D005260:Female; D007839:Functional Laterality; D019398:Genes, BRCA1; D024522:Genes, BRCA2; D020022:Genetic Predisposition to Disease; D006801:Humans; D008875:Middle Aged; D016609:Neoplasms, Second Primary / Q000209:etiology / Q000235:genetics / Q000517:prevention & control; D016017:Odds Ratio; D010375:Pedigree; D017697:Premenopause; D012189:Retrospective Studies; D018570:Risk Assessment; D013629:Tamoxifen / Q000627:therapeutic use*
D018931:Antineoplastic Agents, Hormonal; D013629:Tamoxifen