In:
Cancer Epidemiology, Biomarkers & Prevention, American Association for Cancer Research (AACR), Vol. 21, No. 7 ( 2012-07-01), p. 1089-1096
Abstract:
Background: To evaluate the effect of the cumulative number of ovulatory cycles and its contributing components on the risk of breast cancer among BRCA mutation carriers. Methods: We conducted a matched case–control study on 2,854 pairs of women with a BRCA1 or BRCA2 mutation. Conditional logistic regression was used to estimate the association between the number of ovulatory cycles and various exposures and the risk of breast cancer. Information from a subset of these women enrolled in a prospective cohort study was used to calculate age-specific breast cancer rates. Results: The annual risk of breast cancer decreased with the number of ovulatory cycles experienced (ρ = −0.69; P = 0.03). Age at menarche and duration of breastfeeding were inversely related with risk of breast cancer among BRCA1 (Ptrend & lt; 0.0001) but not among BRCA2 (Ptrend ≥ 0.28) mutation carriers. The reduction in breast cancer risk associated with surgical menopause [OR, 0.52; 95% confidence interval (CI), 0.40–0.66; Ptrend & lt; 0.0001] was greater than that associated with natural menopause (OR, 0.81; 95% CI, 0.62–1.07; Ptrend = 0.14). There was a highly significant reduction in breast cancer risk among women who had an oophorectomy after natural menopause (OR, 0.13; 95% CI, 0.02–0.54; P = 0.006). Conclusions: These data challenge the hypothesis that breast cancer risk can be predicted by the lifetime number of ovulatory cycles in women with a BRCA mutation. Both pre- and postmenopausal oophorectomy protect against breast cancer. Impact: Understanding the basis for the protective effect of oophorectomy has important implications for chemoprevention. Cancer Epidemiol Biomarkers Prev; 21(7); 1089–96. ©2012 AACR.
Type of Medium:
Online Resource
ISSN:
1055-9965
,
1538-7755
DOI:
10.1158/1055-9965.EPI-12-0201
Language:
English
Publisher:
American Association for Cancer Research (AACR)
Publication Date:
2012
detail.hit.zdb_id:
2036781-8
detail.hit.zdb_id:
1153420-5
