Age at first birth and the risk of breast cancer in BRCA1 and BRCA2 mutation carriers.
Abstact
An early age at first full-term birth is associated with a reduction in the subsequent development of breast cancer among women in the general population. A similar effect has not yet been reported among women who carry an inherited BRCA1 or BRCA2 mutation. We conducted a matched case-control study on 1816 pairs of women with a BRCA1 (n = 1405) or BRCA2 (n = 411) mutation in an attempt to elucidate the relationship between age at first full-term pregnancy and the risk of developing breast cancer. Information about the age at first childbirth and other pregnancy-related variables was derived from a questionnaire administered to women during the course of genetic counselling. There was no difference in the mean age at first full-term birth in the cases and controls (24.9 years vs. 24.8 years; P = 0.81, respectively). Compared to women whose first child was born at or before 18 years of age, a later age at first full-term birth did not influence the risk of developing breast cancer (OR = 1.00 per year; 95% CI 0.98-1.03; P-trend = 0.67). Stratification by mutation status did not affect the results. These findings suggest that an early first full-term birth does not confer protection against breast cancer in BRCA mutation carriers. Nonetheless, BRCA mutation carriers opting for a prophylactic oophorectomy as a breast and/or ovarian cancer risk-reducing strategy should complete childbearing prior to age 40 when this prevention modality is most effective.
Authors
- Ainsworth P
- Bellati C
- Chudley A
- Couch F
- Daly M
- Domchek S
- Eisen A
- Eng C
- Evans G
- Fishman D
- Foulkes WD
- Friedman E
- Garber J
- Gershoni-Baruch R
- Ghadirian P
- Isaacs C
- Karlan B
- Kim-Sing C
- Klijn J
- Kotsopoulos J
- Lemire E
- Lubinski J
- Lynch HT
- McKinnon W
- McLennan J
- Merajver S
- Meschino WS
- Moller P
- Narod SA
- Neuhausen SL
- Offit K
- Olsson H
- Osborne M
- Pasche B
- Pasini B
- Provencher D
- Randall S
- Rayson D
- Rennert G
- Saal HM
- Sun P
- Tung N
- Wagner T
- Weitzel J