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Reproductive risk factor associations with lobular and ductal carcinoma in the Carolina Breast Cancer Study.
BACKGROUND: Invasive lobular breast tumors display unique reproductive risk factor profiles. Lobular tumors are predominantly Luminal A subtype, and it is unclear whether reported risk factor associations are independent of molecular subtype. METHODS: Polytomous logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs) for the associations between risk factors and histologic subtype [ductal (n = 2,856), lobular (n = 326), and mixed ductal-lobular (n = 473)] in the Carolina Breast Cancer Study (1993-2013). Three-marker immunohistochemical clinical subtypes were defined as Luminal A (ER+ or PR+/HER2-), Luminal B (ER+ or PR+/HER2+), Triple Negative (ER-/PR-/HER2-), and HER2+ (ER-/PR-/HER2+). RESULTS: In case-case analyses compared to ductal, lobular tumors were significantly associated with lactation duration > 12 months [OR 1.86, 95% CI (1.33-2.60)], age at first birth ≥ 26 years [OR: 1.35, 95% CI: (1.03-1.78)], and current oral contraceptive use [OR: 1.86, 95% CI: (1.08-3.20)]. Differences in risk factor associations between ductal and lobular tumors persisted after restricting to Luminal A subtype. CONCLUSIONS: Lobular tumors were associated with older age at first birth, increased lactation duration, and current oral contraceptive use. Etiologic heterogeneity by histology persisted after restricting to Luminal A subtype, suggesting both tumor histology and intrinsic subtype play integral parts in breast cancer risk.
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Related Subject Headings
- Risk Factors
- Receptors, Progesterone
- Receptors, Estrogen
- Receptor, erbB-2
- Receptor, ErbB-2
- Odds Ratio
- Middle Aged
- Logistic Models
- Lactation
- Humans
Citation
![Journal cover image](https://secure.syndetics.com/index.aspx?isbn=/lc.gif&issn=1573-7225&client=dukeuniv)
Published In
DOI
EISSN
Publication Date
Volume
Issue
Start / End Page
Location
Related Subject Headings
- Risk Factors
- Receptors, Progesterone
- Receptors, Estrogen
- Receptor, erbB-2
- Receptor, ErbB-2
- Odds Ratio
- Middle Aged
- Logistic Models
- Lactation
- Humans