Palmer Julie R, Viscidi Emma, Troester Melissa A, Hong Chi-Chen, Schedin Pepper, Bethea Traci N, Bandera Elisa V, Borges Virginia, McKinnon Craig, Haiman Christopher A, Lunetta Kathryn, Kolonel Laurence N, Rosenberg Lynn, Olshan Andrew F, Ambrosone Christine B
Slone Epidemiology Center at Boston University, Boston, MA (JRP, EV, TNB, LR); University of North Carolina Lineberger Cancer Center, Chapel Hill, NC (MAT, AFO); Roswell Park Cancer Institute, Buffalo, NY (CCH, CBA); University of Colorado Denver School of Medicine, Denver, CO (PS, VB); Rutgers Cancer Institute of New Jersey, New Brunswick, NJ (EVB); Boston University School of Public Health, Boston, MA (CM, KL); Department of Preventive Medicine and Norris Comprehensive Cancer Cencer, University of Southern California Keck School of Medicine, Los Angeles, CA (CAH); Department of Public Health Sciences, University of Hawaii School of Medicine, Honolulu, HI (LNK).
J Natl Cancer Inst. 2014 Sep 15;106(10). doi: 10.1093/jnci/dju237. Print 2014 Oct.
African American (AA) women have a disproportionately high incidence of estrogen receptor-negative (ER-) breast cancer, a subtype with a largely unexplained etiology. Because childbearing patterns also differ by race/ethnicity, with higher parity and a lower prevalence of lactation in AA women, we investigated the relation of parity and lactation to risk of specific breast cancer subtypes.
Questionnaire data from two cohort and two case-control studies of breast cancer in AA women were combined and harmonized. Case patients were classified as ER+ (n = 2446), ER- (n = 1252), or triple negative (ER-, PR-, HER2-; n = 567) based on pathology data; there were 14180 control patients. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated in polytomous logistic regression analysis with adjustment for study, age, reproductive and other risk factors.
ORs for parity relative to nulliparity was 0.92 (95% CI = 0.81 to 1.03) for ER+, 1.33 (95% CI = 1.11 to 1.59) for ER-, and 1.37 (95% CI = 1.06 to 1.70) for triple-negative breast cancer. Lactation was associated with a reduced risk of ER- (OR = 0.81, 95% CI = 0.69 to 0.95) but not ER+ cancer. ER- cancer risk increased with each additional birth in women who had not breastfed, with an OR of 1.68 (95% CI = 1.15 to 2.44) for 4 or more births relative to one birth with lactation.
The findings suggest that parous women who have not breastfed are at increased risk of ER- and triple-negative breast cancer. Promotion of lactation may be an effective tool for reducing occurrence of the subtypes that contribute disproportionately to breast cancer mortality.
非裔美国（AA）女性雌激素受体阴性（ER-）乳腺癌的发病率高得不成比例，这是一种病因很大程度上不明的亚型。由于生育模式也因种族/族裔而异，AA女性的产次较高且哺乳率较低，我们研究了产次和哺乳与特定乳腺癌亚型风险的关系。
对两项AA女性乳腺癌队列研究和两项病例对照研究的问卷数据进行合并和统一。根据病理数据，将病例患者分为ER+（n = 2446）、ER-（n = 1252）或三阴性（ER-、PR-、HER2-；n = 567）；有14180名对照患者。在多分类逻辑回归分析中估计比值比（OR）和95%置信区间（CI），并对研究、年龄、生殖和其他风险因素进行调整。
ER+的产次相对于未生育的比值比为0.92（95%CI = 0.81至1.03），ER-为1.33（95%CI = 1.11至1.59），三阴性乳腺癌为1.37（95%CI = 1.06至1.70）。哺乳与ER-风险降低相关（OR = 0.81，95%CI = 0.69至0.95），但与ER+癌症无关。未哺乳的女性每多生育一次，ER-癌症风险增加，4次或更多次生育相对于一次哺乳生育的OR为1.68（95%CI = 1.15至2.44）。
研究结果表明，未哺乳的经产妇患ER-和三阴性乳腺癌的风险增加。促进哺乳可能是减少对乳腺癌死亡率贡献不成比例的亚型发生的有效工具。
