Risk factors for estrogen receptor positive ductal carcinoma in situ of the breast in African American women

Background: Compared to U.S. white women, African American women are more likely to die from ductal carcinoma in situ (DCIS). Elucidation of risk factors for DCIS in African American women may provide opportunities for risk reduction. Methods: We used data from three epidemiologic studies in the African American Breast Cancer Epidemiology and Risk Consortium to study risk factors for estrogen receptor (ER) positive DCIS (488 cases; 13,830 controls). Results were compared to associations observed for ER+ invasive breast cancer (n = 2,099). Results: First degree family history of breast cancer was associated with increased risk of ER+ DCIS [odds ratio (OR): 1.69, 95% confidence interval (CI): 1.31, 2.17]. Oral contraceptive use within the past 10 years (vs. never) was also associated with increased risk (OR: 1.43, 95%CI: 1.03, 1.97), as was late age at first birth (≥25 years vs. <20 years) (OR: 1.26, 95%CI: 0.96, 1.67). Risk was reduced in women with older age at menarche (≥15 years vs. <11 years) (OR: 0.62, 95%CI: 0.42, 0.93) and higher body mass index (BMI) in early adulthood (≥25 vs. <20 kg/m2 at age 18 or 21) (OR: 0.75, 95%CI: 0.55, 1.01). There was a positive association of recent BMI with risk in postmenopausal women only. In general, associations of risk factors for ER+ DCIS were similar in magnitude and direction to those for invasive ER+ breast cancer. Conclusions: Our findings suggest that most risk factors for invasive ER+ breast cancer are also associated with increased risk of ER+ DCIS among African American women

Postmenopausal female hormone use and estrogen receptor-positive and -negative breast cancer in african American women

Background: Use of estrogen with progestin (combination therapy) is associated with increased incidence of estrogen receptor-positive (ER+) breast cancer in observational studies and randomized trials among postmenopausal white women. Whether this is also the case among African American women is not established. Methods: Using data from the AMBER consortium collected from 1993 to 2013, we assessed use of estrogen alone and of combination therapy in relation to ER+ and ER-negative (ER-) breast cancer risk in postmenopausal African American women, based on 1132 ER+ case patients, 512 ER- case patients, and 6693 control patients. Odds ratios (ORs) and confidence intervals (CIs) were estimated using multinomial logistic regression with control for breast cancer risk factors. Results: Forty-seven percent of control patients had used estrogen alone, combination therapy, or both. The odds ratio for ER+ breast cancer associated with combination use, relative to never use of either estrogen alone or combination therapy, was 1.50 (95% CI = 1.25 to 1.79). The increase was greater for recent (OR = 1.55, 95% CI = 1.21 to 1.99) and long-term use (OR = 1.75, 95% CI = 1.13 to 2.73) and among nonobese women (OR = 1.91, 95% CI = 1.29 to 2.83). Breast cancer risk was increased regardless of the interval between onset of menopause and initiation of combination use (OR = 1.43, 95% CI = 1.11 to 1.85, for <5 year interval; OR = 1.78, 95% CI = 1.34 to 2.37, for ≥5 year interval). Combination use was not associated with risk of ER- breast cancer, and use of estrogen alone was not associated with risk of either ER+ or ER- breast cancer. Conclusion: Use of estrogen with progestin increases risk of ER+ breast cancer in African American women. A decrease in use would be expected to reduce the number of ER+ cancers

Epidemiology of basal-like and luminal breast cancers among black women in the amber consortium

Background: Evidence suggests etiologic heterogeneity among breast cancer subtypes. Previous studies with six-marker IHC classification of intrinsic subtypes included small numbers of black women. Methods: Using centralized laboratory results for estrogen receptor (ER), progesterone receptor, HER2, proliferation marker, Ki-67, EGFR, and cytokeratin (CK)5/6, we estimated case-only and case. control ORs for established breast cancer risk factors among cases (n.2,354) and controls (n.2,932) in the African American Breast Cancer Epidemiology and Risk (AMBER) consortium. ORs were estimated by ER status and intrinsic subtype using adjusted logistic regression. Results: Case-only analyses by ER status showed etiologic heterogeneity by age at menarche, parity (vs. nulliparity), and age at first birth. In case.control analyses for intrinsic subtype, increased body mass index and waist-to-hip ratio (WHR) were associated with increased risk of luminal A subtype, whereas older age at menarche and parity, regardless of breastfeeding, were associated with reduced risk. For basal-like cancers, parity without breastfeeding and increasing WHR were associated with increased risk, whereas breastfeeding and age ≥25 years at first birth were associated with reduced risk among parous women. Basal-like and ER-/ HER2+ subtypes had earlier age-at-incidence distribution relative to luminal subtypes. Conclusions: Breast cancer subtypes showed distinct etiologic profiles in theAMBERconsortium, a study of more than 5,000 black women with centrally assessed tumor biospecimens. Impact: Among black women, high WHR and parity without breastfeeding are emerging as important intervention points to reduce the incidence of basal-like breast cancer

Biology and etiology of young-onset breast cancers among premenopausal African American women: Results from the AMBER Consortium

Background: African American (AA) women have higher incidence of aggressive, young-onset (<40 years) breast cancers. Young- and older-onset disease may have distinct tumor biologies and etiologies; however, studies investigating age differences among AA women have been rare and generally underpowered. Methods: We examined tumor characteristics and breast cancer risk factors associated with premenopausal young (<40) vs. older (40) AA women's breast cancer in the African American Breast Cancer Epidemiology and Risk Consortium (2,008 cases and 5,144 controls). Unconditional logistic regression models assessed heterogeneity of tumor biology and risk factor associations by age, overall, and by estrogen receptor status. Results: Premenopausal AA women <40 years had higher frequency of poorer-prognosis tumor characteristics compared with older women, including negative estrogen and progesterone receptor status, triple-negative subtype, higher grade, higher stage, and larger tumors. Adiposity (i.e., waist-to-hip ratio) and family history of breast cancer were more strongly associated with young-onset disease [case–control OR ¼ 1.46, 95% confidence interval (CI) ¼ 1.04–2.05; OR ¼ 3.10, 95% CI ¼ 2.08–4.63, respectively] compared with older-onset disease (OR ¼ 1.11, 95% CI ¼ 0.91–1.35; OR ¼ 1.57, 95% CI ¼ 1.26–1.94). Breastfeeding showed a slight inverse risk association among young women (OR ¼ 0.70, 95% CI ¼ 0.43–1.16). Oral contraceptive use was associated with increased risk regardless of age. Considering various cutoff points for young age (<40, <45, <50), age-related heterogeneity was greatest when <40 was used. Conclusions: Among premenopausal AA women, diagnosis before age 40 is associated with more aggressive breast tumor biology and some etiologic differences. Impact: Modifiable risk factors including breastfeeding, adiposity, and oral contraceptive use may be important targets for mitigating harms of young-onset breast cancer

Dairy foods, calcium, and risk of breast cancer overall and for subtypes defined by estrogen receptor status: a pooled analysis of 21 cohort studies

Background: Epidemiologic studies examining the relations between dairy product and calcium intakes and breast cancer have been inconclusive, especially for tumor subtypes. Objective: To evaluate the associations between intakes of specific dairy products and calcium and risk of breast cancer overall and for subtypes defined by estrogen receptor (ER) status. Method: We pooled the individual-level data of over 1 million women who were followed for a maximum of 8-20 years across studies. Associations were evaluated for dairy product and calcium intakes and risk of incident invasive breast cancer overall (n = 37,861 cases) and by subtypes defined by ER status. Study-specific multivariable hazard ratios (HRs) were estimated and then combined using random-effects models. Results: Overall, no clear association was observed between the consumption of specific dairy foods, dietary (from foods only) calcium, and total (from foods and supplements) calcium, and risk of overall breast cancer. Although each dairy product showed a null or very weak inverse association with risk of overall breast cancer (P, test for trend >0.05 for all), differences by ER status were suggested for yogurt and cottage/ricotta cheese with associations observed for ER-negative tumors only (pooled HR = 0.90, 95% CI: 0.83, 0.98 comparing >= 60 g/d with = 25 g/d with Conclusion: Our study shows that adult dairy or calcium consumption is unlikely to associate with a higher risk of breast cancer and that higher yogurt and cottage/ricotta cheese intakes were inversely associated with the risk of ER-negative breast cancer, a less hormonally dependent subtype with poor prognosis. Future studies on fermented dairy products, earlier life exposures, ER-negative breast cancer, and different racial/ethnic populations may further elucidate the relation

Dairy foods, calcium, and risk of breast cancer overall and for subtypes defined by estrogen receptor status: a pooled analysis of 21 cohort studies

Background: Epidemiologic studies examining the relations between dairy product and calcium intakes and breast cancer have been inconclusive, especially for tumor subtypes. Objective: To evaluate the associations between intakes of specific dairy products and calcium and risk of breast cancer overall and for subtypes defined by estrogen receptor (ER) status. Method: We pooled the individual-level data of over 1 million women who were followed for a maximum of 8-20 years across studies. Associations were evaluated for dairy product and calcium intakes and risk of incident invasive breast cancer overall (n = 37,861 cases) and by subtypes defined by ER status. Study-specific multivariable hazard ratios (HRs) were estimated and then combined using random-effects models. Results: Overall, no clear association was observed between the consumption of specific dairy foods, dietary (from foods only) calcium, and total (from foods and supplements) calcium, and risk of overall breast cancer. Although each dairy product showed a null or very weak inverse association with risk of overall breast cancer (P, test for trend >0.05 for all), differences by ER status were suggested for yogurt and cottage/ricotta cheese with associations observed for ER-negative tumors only (pooled HR = 0.90, 95% CI: 0.83, 0.98 comparing >= 60 g/d with = 25 g/d with Conclusion: Our study shows that adult dairy or calcium consumption is unlikely to associate with a higher risk of breast cancer and that higher yogurt and cottage/ricotta cheese intakes were inversely associated with the risk of ER-negative breast cancer, a less hormonally dependent subtype with poor prognosis. Future studies on fermented dairy products, earlier life exposures, ER-negative breast cancer, and different racial/ethnic populations may further elucidate the relation