Oral Contraceptive Use and Estrogen/Progesterone Receptor-Negative Breast Cancer among African American Women

Slone Epidemiology Center at Boston University, 1010 Commonwealth Avenue, Boston, MA 02215, USA.
Cancer Epidemiology Biomarkers & Prevention (Impact Factor: 4.13). 08/2010; 19(8):2073-9. DOI: 10.1158/1055-9965.EPI-10-0428
Source: PubMed


Oral contraceptive formulations have changed over time, making it relevant to assess the effect of more recent formulations on breast cancer risk. In addition, some studies have found stronger positive associations of oral contraceptive use with estrogen receptor-negative (ER(-)) than with ER-positive (ER(+)) breast cancer. We carried out the first assessment of the effect of oral contraceptive use on the incidence of breast cancer classified by receptor status among African American women, a group disproportionately affected by ER(-) cancer.
We followed 53,848 Black Women's Health Study participants from 1995 to 2007 through biennial health questionnaires, in which participants reported information about incident breast cancer, oral contraceptive use, and breast cancer risk factors. Pathology information was obtained on receptor status for 789 incident cases. Incidence rate ratios (IRR) with 95% confidence intervals (95% CI) were derived from Cox regression models with control for confounding factors.
Ever use of oral contraceptives was more strongly associated with ER(-)PR(-) breast cancer (279 cases; IRR, 1.65; 95% CI, 1.19-2.30) than with ER(+)PR(+) cancer (386 cases; IRR, 1.11; 95% CI, 0.86-1.42). The risk of ER(-)PR(-) breast cancer increased with increasing duration of use among recent users.
These results indicate that the oral contraceptive formulations used in recent decades increase breast cancer risk in African American women, with a greater effect for ER(-) than ER(+) cancer.
Mechanisms to explain the adverse influence of oral contraceptive use on ER(-) breast cancer need to be elucidated.

Download full-text


Available from: Deborah Boggs Bookwalter
  • Source
    • "In particular, we focused on the associations with parity and breastfeeding and, more importantly, evaluated whether the reduction in risk from breastfeeding in the presence of multiparity extended to higher risk women. We also focused on evaluating oral contraceptive (OC) use, which has previously been associated with an increased risk of ER À PR À cancer (Althuis et al, 2004; Rosenberg et al, 2010). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Background: Oestrogen receptor (ER)- and progesterone receptor (PR)-negative (ER−PR−) breast cancer is associated with poorer prognosis compared with other breast cancer subtypes. High parity has been associated with an increased risk of ER−PR− cancer, but emerging evidence suggests that breastfeeding may reduce this risk. Whether this potential breastfeeding benefit extends to women at high risk of breast cancer remains critical to understand for prevention. Methods: Using population-based ascertained cases (n=4011) and controls (2997) from the Breast Cancer Family Registry, we examined reproductive risk factors in relation to ER and PR status. Results: High parity (⩾3 live births) without breastfeeding was positively associated only with ER−PR− tumours (odds ratio (OR)=1.57, 95% confidence interval (CI), 1.10–2.24); there was no association with parity in women who breastfed (OR=0.93, 95% CI 0.71–1.22). Across all race/ethnicities, associations for ER−PR− cancer were higher among women who did not breastfeed than among women who did. Oral contraceptive (OC) use before 1975 was associated with an increased risk of ER−PR− cancer only (OR=1.32, 95% CI 1.04–1.67). For women who began OC use in 1975 or later there was no increased risk. Conclusions: Our findings support that there are modifiable factors for ER−PR− breast cancer and that breastfeeding in particular may mitigate the increased risk of ER−PR− cancers seen from multiparity.
    Full-text · Article · Feb 2014 · British Journal of Cancer
  • Source
    • "OC use has been extensively studied by many epidemiological studies and most studies have found either no association or a moderate increased risk of overall breast cancer, particularly among very young women and recent OC users [26]. More recent case–control studies investigating the risk of HR-defined breast cancer have started showing relationships of OC use with HR-negative breast cancer [33-37]. In the current study, we were unable to confirm significant risk associations of ever OC use and a longer duration of OC use with HR-negative tumors. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The association of reproductive factors with hormone receptor (HR)-negative breast tumors remains uncertain. Within the EPIC cohort, Cox proportional hazards models were used to describe the relationships of reproductive factors (menarcheal age, time between menarche and first pregnancy, parity, number of children, age at first and last pregnancies, time since last full-term childbirth, breastfeeding, age at menopause, ever having an abortion and use of oral contraceptives [OC]) with risk of ER-PR- (n = 998) and ER+PR+ (n = 3,567) breast tumors. A later first full-term childbirth was associated with increased risk of ER+PR+ tumors but not with risk of ER-PR- tumors (>=35 vs. <=19 years HR: 1.47 [95%CI 1.15-1.88] ptrend < 0.001 for ER+PR+ tumors; >=35 vs. <=19 years HR: 0.93 [95%CI 0.53-1.65] ptrend = 0.96 for ER-PR- tumors; Phet = 0.03). The risk associations of menarcheal age, and time period between menarche and first full-term childbirth with ER-PR-tumors were in the similar direction with risk of ER+PR+ tumors (phet = 0.50), although weaker in magnitude and statistically only borderline significant. Other parity related factors such as ever a full-term birth, number of births, age- and time since last birth were associated only with ER+PR+ malignancies, however no statistical heterogeneity between breast cancer subtypes was observed. Breastfeeding and OC use were generally not associated with breast cancer subtype risk. Our study provides possible evidence that age at menarche, and time between menarche and first full-term childbirth may be associated with the etiology of both HR-negative and HR-positive malignancies, although the associations with HR-negative breast cancer were only borderline significant.
    Full-text · Article · Dec 2013 · BMC Cancer
  • Source
    • "The evidence on a link between hormonal contraceptives, particularly oral contraceptives, and cancer is mixed – the pill protects against uterine and endometrial cancer, but it is less clear how breast cancer risk is affected. While some large-scale studies find no evidence of a breast cancer-pill link (e.g., Marchbanks et al. 2002), one study of non- Hispanic blacks found a statistically significant but slight increase in a rare but aggressive form of breast cancer (Rosenberg et al. 2010). Thus, non-Hispanic black women may be drastically overestimating the risks of side effects when using contraception, but their fears are not necessarily unfounded. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Despite extensive research examining the correlates of unintended fertility, it remains a puzzle as to why racial and ethnic minorities are more likely to experience an unintended birth than non-Hispanic whites. This paper focuses on sexual literacy, a potential precursor of unintended fertility. Analyses use a unique dataset of unmarried young adults aged 18-29, the 2009 Survey of Unmarried Young Adults' Contraceptive Knowledge and Practices, to examine beliefs regarding pregnancy risks, pregnancy fatalism, and contraceptive side effects. At the bivariate level, foreign-born Hispanics hold more erroneous beliefs about the risk of pregnancy than other groups, and non-Hispanic blacks are more likely to believe in contraceptive side effects than non-Hispanic whites. Both foreign-born Hispanics and non-Hispanic blacks are more likely than non-Hispanic whites to hold a fatalistic view towards pregnancy. Race-ethnic differences are attenuated for pregnancy misperceptions and fatalism in multivariate models controlling for sources of health information, sexual and fertility experiences, and sociodemographic characteristics. However, non-Hispanic blacks remain more likely than non-Hispanic whites to believe there is a high chance of reduced sexual desire and serious health consequences when using hormonal contraceptives. These differences may contribute to race-ethnic variation in contraceptive use and, ultimately, unintended fertility.
    Preview · Article · Dec 2012 · Race and Social Problems
Show more