Spontaneous and therapeutic abortions and the risk of breast cancer among BRCA mutation carriers.
BACKGROUND
BRCA1 and BRCA2 mutation carriers are at increased risk for developing both breast and ovarian cancer. It has been suggested that carriers of BRCA1/2 mutations may also be at increased risk of having recurrent (three or more) miscarriages. Several reproductive factors have been shown to influence the risk of breast cancer in mutation carriers, but the effects of spontaneous and therapeutic abortions on the risk of hereditary breast cancer risk have not been well studied to date.


METHODS
In a matched case-control study, the frequencies of spontaneous abortions were compared among 1,878 BRCA1 mutation carriers, 950 BRCA2 mutation carriers and 657 related non-carrier controls. The rates of spontaneous and therapeutic abortions were compared for carriers with and without breast cancer.


RESULTS
There was no difference in the rate of spontaneous abortions between carriers of BRCA1 or BRCA2 mutations and non-carriers. The number of spontaneous abortions was not associated with breast cancer risk among BRCA1 or BRCA2 mutation carriers. However, BRCA2 carriers who had two or more therapeutic abortions faced a 64% decrease in the risk of breast cancer (odds ratio = 0.36; 95% confidence interval 0.16-0.83; p = 0.02).


CONCLUSIONS
Carrying a BRCA1 or BRCA2 mutation is not a risk factor for spontaneous abortions and spontaneous abortions do not appear to influence the risk of breast cancer in carriers of BRCA1 or BRCA2 mutations. However, having two or more therapeutic abortions may be associated with a lowered risk of breast cancer among BRCA2 carriers.
The Suzanne Levy Gertner Oncogenetics Unit, The Chaim Sheba Medical Center, Tel-Hashomer, Israel, and the Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
Eitan
E
Friedman
Joanne
J
Kotsopoulos
Jan
J
Lubinski
Henry T
HT
Lynch
Parviz
P
Ghadirian
Susan L
SL
Neuhausen
Claudine
C
Isaacs
Barbara
B
Weber
William D
WD
Foulkes
Pal
P
Moller
Barry
B
Rosen
Charmaine
C
Kim-Sing
Ruth
R
Gershoni-Baruch
Peter
P
Ainsworth
Mary
M
Daly
Nadine
N
Tung
Andrea
A
Eisen
Olufunmilayo I
OI
Olopade
Beth
B
Karlan
Howard M
HM
Saal
Judy E
JE
Garber
Gad
G
Rennert
Dawna
D
Gilchrist
Charis
C
Eng
Kenneth
K
Offit
Michael
M
Osborne
Ping
P
Sun
Steven A
SA
Narod
D000022:Abortion, Spontaneous / Q000453:epidemiology*; D000032:Abortion, Therapeutic / Q000706:statistics & numerical data*; D001943:Breast Neoplasms / Q000453:epidemiology / Q000235:genetics*; D016022:Case-Control Studies; D005260:Female; D019398:Genes, BRCA1; D024522:Genes, BRCA2; D006580:Genetic Carrier Screening; D006801:Humans; D009154:Mutation; D011247:Pregnancy; D018570:Risk Assessment; D012307:Risk Factors