Abstract B12: Associations between invasive breast cancer with and without a DCIS component and breast cancer risk factors in African American and European American women
Authors: Ruszczyk Melanie , Zirpoli Gary , Pawlish Karen , Masso-Welch Patricia , Ambrosone Christine B. , Bandera Elisa , Bovbjerg Dana H. , Jandorf Lina , Hong Chi-Chen , Hwang Helena , Ciupak Gregory , Davis Warren , McCann Susan E. 
Published: June 2012

Introduction: Breast cancer presents as several clinically distinct forms, including invasive ductal carcinoma (IDC) with an associated ductal carcinoma in situ (DCIS) component, and pure IDC. The absence of concomitant DCIS was previously associated with a significantly worse prognosis for IDC, even after adjustment for stage and tumor size. Evidence from gene expression studies suggests that the absence of a DCIS component is associated with an altered tumor microenvironment, which may involve a distinct pathway of cancer development, with unique risk factors and prognoses. The absence of a DCIS component in IDC has not previously been examined in relation to the breast cancer disparities between African-American (AA) and European-American (EA) women.

Methods: IDC breast cancer patients with or without a DCIS component were identified by examining pathological reports from the Women's Circle of Health Study, an on-going case-control study examining racial disparities in women diagnosed with breast cancer in NYC and NJ. Through in-person interviews information was collected on known and suspected breast cancer risk factors. In this case-case analysis, we examined these factors in relation to IDC with and without a DCIS component, adjusting for self-reported race and also stratified by race. Interactions were assessed with the Wald Chi-square. Odds ratios (ORs) and 95% confidence intervals (CIs) were derived to estimate the odds of having pure IDC compared to patients with a DCIS component.

Results: Of 729 women with IDC, 19.5% were confirmed to have pure IDC and 80.5% IDC with a DCIS component. EA women were less likely than AA women to present with pure IDC without a DCIS component (OR=0.66; 95% CI 0.43–0.99). Women who breastfed were less likely to have pure IDC than IDC with a DCIS component (OR=0.65; 95% CI 0.40–1.04). Stratified analyses by race did not reveal major differences from unstratified analyses for breastfeeding (OR=0.64; 95% CI 0.35–1.16, OR=0.68; 95% CI 0.28–1.64 in AA and EA women, respectively). AA women with a body mass index (BMI) ≥30 compared to a BMI &lt;25 were less likely to have pure IDC than IDC with DCIS (OR=0.52; 95% CI 0.25–0.97), whereas EA women with a high BMI were more likely to have pure IDC (OR=1.36; 95% CI 0.67–2.76, p for interaction=0.01). Pure IDC was directly and inversely associated with family history of breast cancer in EA and AA women, respectively (OR=1.89; 95% CI 1.01–3.55, OR=0.84; 95% CI 0.42–1.67, respectively, p for interaction=0.09).

Conclusion: Compared to EA women, AA women are more likely to present with pure IDC without a DCIS component. Stratified analyses suggest that risk factors associated with pure IDC may be significantly different between AA and EA women.

Citation Information: Cancer Prev Res 2011;4(10 Suppl):B12.