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.
Friedman
Eitan
E
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.
Kotsopoulos
Joanne
J
Lubinski
Jan
J
Lynch
Henry T
HT
Ghadirian
Parviz
P
Neuhausen
Susan L
SL
Isaacs
Claudine
C
Weber
Barbara
B
Foulkes
William D
WD
Moller
Pal
P
Rosen
Barry
B
Kim-Sing
Charmaine
C
Gershoni-Baruch
Ruth
R
Ainsworth
Peter
P
Daly
Mary
M
Tung
Nadine
N
Eisen
Andrea
A
Olopade
Olufunmilayo I
OI
Karlan
Beth
B
Saal
Howard M
HM
Garber
Judy E
JE
Rennert
Gad
G
Gilchrist
Dawna
D
Eng
Charis
C
Offit
Kenneth
K
Osborne
Michael
M
Sun
Ping
P
Narod
Steven A
SA
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