Ma Huiyan, Ursin Giske, Xu Xinxin, Lee Eunjung, Togawa Kayo, Duan Lei, Lu Yani, Malone Kathleen E, Marchbanks Polly A, McDonald Jill A, Simon Michael S, Folger Suzanne G, Sullivan-Halley Jane, Deapen Dennis M, Press Michael F, Bernstein Leslie
Department of Population Sciences, Beckman Research Institute, 1500 East Duarte Rd. Duarte, City of Hope, CA, 91010, USA.
Cancer Registry of Norway, Oslo, Norway.
Breast Cancer Res. 2017 Jan 13;19(1):6. doi: 10.1186/s13058-016-0799-9.
Early age at menarche, nulliparity, late age at first completed pregnancy, and never having breastfed, are established breast cancer risk factors. However, among breast cancer subtypes, it remains unclear whether all of these are risk factors for triple-negative breast cancer (TNBC).
We evaluated the associations of these reproductive factors with TNBC, in 2658 patients with breast cancer (including 554 with TNBC) and 2448 controls aged 20-64 years, who participated in one of the three population-based case-control studies: the Women's Contraceptive and Reproductive Experiences Study, the Women's Breast Carcinoma in situ Study, or the Women's Learning the Influence of Family and Environment Study. We used multivariable polychotomous unconditional logistic regression methods to conduct case-control comparisons among breast cancer subtypes defined by estrogen receptor, progesterone receptor, and human epidermal growth factor receptor-2 expression status.
TNBC risk decreased with increasing duration of breastfeeding (P = 0.006), but age at menarche, age at first completed pregnancy, and nulliparity were not associated with risk of TNBC. Parous women who breastfed for at least one year had a 31% lower risk of TNBC than parous women who had never breastfed (odds ratio, OR = 0.69; 95% confidence interval, CI = 0.50-0.96). The association between breastfeeding and risk of TNBC was modified by age and race. Parous African-American women aged 20-44 years who breastfed for 6 months or longer had an 82% lower risk of TNBC than their counterparts who had never breastfed (OR = 0.18, 95% CI = 0.07-0.46).
Our data indicate that breastfeeding decreases the risk of TNBC, especially for younger African-American women.
初潮年龄早、未生育、首次足月妊娠年龄晚以及从未哺乳是已确定的乳腺癌风险因素。然而，在乳腺癌亚型中，尚不清楚所有这些因素是否都是三阴性乳腺癌（TNBC）的风险因素。
我们评估了这些生殖因素与TNBC之间的关联，研究对象为2658例乳腺癌患者（包括554例TNBC患者）和2448例年龄在20 - 64岁的对照者，他们参与了三项基于人群的病例对照研究之一：女性避孕与生殖经历研究、女性原位乳腺癌研究或女性了解家庭与环境影响研究。我们使用多变量多分类无条件逻辑回归方法，对根据雌激素受体、孕激素受体和人表皮生长因子受体2表达状态定义的乳腺癌亚型进行病例对照比较。
TNBC风险随哺乳时间延长而降低（P = 0.006），但初潮年龄、首次足月妊娠年龄和未生育与TNBC风险无关。哺乳至少一年的经产妇患TNBC的风险比从未哺乳的经产妇低31%（优势比，OR = 0.69；95%置信区间，CI = 0.50 - 0.96）。哺乳与TNBC风险之间的关联因年龄和种族而异。年龄在20 - 44岁、哺乳6个月或更长时间的非裔美国经产妇患TNBC的风险比从未哺乳的同类女性低82%（OR = 0.18，95% CI = 0.07 - 0.46）。
我们的数据表明，哺乳可降低TNBC风险，尤其是对年轻的非裔美国女性。
