A case–control study of reproductive factors associated with subtypes of breast cancer in Northeast China

Abstract

Based on the expression of estrogen receptor (ER), progesterone receptor (PR) and HER2/neu (HER2), breast cancer is classified into several subtypes: luminal A (ER+ and/or PR+, HER2-), luminal B (ER+ and/or PR+, HER2+), HER2-overexpressing (ER-, PR-, and HER2+) and triple-negative (ER-, PR-, and HER2-). The aim of this case-control study is to determine reproductive factors associated with breast cancer subtypes in Chinese women. A total of 1,417 patients diagnosed with breast cancer in the First Affiliated Hospital, China Medical University, Shenyang, China between 2001 and 2009 and 1,587 matched controls without a prior breast cancer were enrolled. Personal interviews were conducted to obtain information on reproductive characteristics and clinical history. Relationships between the factors and the subtypes of breast cancer were examined using logistic regression to compute odds ratios (OR) and 95% confidence intervals (CI). Notably, luminal A (50.0%) was the most prevalent subtype relative to luminal B (15.10%), HER2-overexpressing (10.87%) and triple-negative (23.08%). Menarche at an early age was associated with a reduced risk of luminal A (OR, 2.35; 95% CI, 1.45-3.81). Breastfeeding protected parous women from any subtype of breast cancer. Postmenopause and spontaneous abortion were inversely associated with the risk of luminal tumors. By contrast, multiparity, family history of breast cancer and induced abortion increased the risk of breast cancer. Collectively, our findings suggest that reproductive factors such as age at menarche, parity, breastfeeding, menopausal status and abortion history have different effects on the subtypes of breast cancer in Chinese women.

Oral Contraceptives, Abortion and Breast Cancer Risk: a Case Control Study in Saudi Arabia

“…Another Report from Turkey showed no association between stage IV breast cancer and OCP use (Uyeturk et al, 2013). A study from China showed that reproductive factors such as age at menarche, parity, breastfeeding, menopausal status and abortion history have different effects on the subtypes of breast cancer in their population (Xing et al, 2010).…”

Comparison of clinicopathological characteristics and prognoses between bilateral and unilateral breast cancer

“…This may suggest diVerent biologic behavior of breast cancer among diVerent races; in Western countries, about 75% of breast cancers were hormone positive (Niemeier et al 2010), whereas this percentage was only 65.1% in China (Xing et al 2010). In addition, the peak age for breast cancer in Asia was 40-50 years, whereas it was 60-70 years in the West (Leong et al 2010).…”

Heterogeneity of epidemiological factors by breast tumor subtypes in Korean women: A case-case study

“…8,11 Furthermore, there have been many studies that compared epidemiological factors between tumor subtypes based on hormone receptor (HR) and HER2 status in the Western population [12][13][14][15][16][17][18][19] ; however, there has been only a few studies in the Asian population. 20,21 In this study, we describe the characteristics of breast cancer classified into tumor subtypes based on ER, PR and HER2 statuses and assess the heterogeneity in association with the epidemiological factors within tumor subtypes as evidence for the etiological differences between breast cancer subtypes through casecase analyses.…”