Abstract
Background: In a recent study, the Carolina Breast Cancer Study found that mortality rates were significantly higher in African American women (AAW) compared to Caucasian women (CW) with luminal A breast cancer. This disparity may be attributable to social and/or molecular differences. Here, we evaluated demographic data from AAW and CW with luminal A breast cancer to determine whether any factors differ between populations.
Methods: The database of the Clinical Breast Care Project was queried to identify all AAW (n=115) and CW patients (n=596) with ER+/HER2- breast cancer. Demographic data recorded at the time of diagnosis were compared between populations using chi-square or Student's t-test. A cutoff of P<0.05 was used to define significance.
Results: Age at diagnosis or menarche, parity, breastfeeding, education levels, exercise, fat intake, smoking and presence of heart disease and diabetes did not differ significantly between populations. Significantly more AAW began using oral contraceptives and were parous before age 18 (28% and 16%) compared to CW (7% and 4%). AAW were more likely to be obese (51% compared to 29%) and to perform at least monthly breast self-exams (97% compared to 80%) and to have hypertension (50% compared to 40%). AAW consumed significantly lower levels of caffeine (439mg/day compared to 983 mg/day) and alcohol (43% compared to 21% non-drinkers) than CW and were less likely to be married (52% compared to 74%). Pathologically, tumors from AAW and CW did not differ for stage or lymph node status, however, luminal A tumors from AAW were significantly more likely to be poorly-differentiated (25% compared to 14%) and were larger (33% compared to 21%) than those from CW.
Discussion: Although luminal A tumors are considered the most favorable breast tumor subtype, ER+/HER2- tumors from AAW were larger and of higher grade than those from CW. It is not clear how differences in caffeine and alcohol consumption may impact outcome in women with luminal A breast tumors, however, use of oral contraceptives during adolescence, pregnancy at an early age (<20 years) and increased inflammation in the breasts of obese women have been associated with higher grade and poorer prognosis. In addition, women who are married have a more favorable prognosis than those who are single, divorced or widowed and patients with hypertension has been associated with increased breast cancer mortality. Together, these demographic factors may contribute to the outcome disparity detected in AAW compared to CW with luminal A breast cancer.
Citation Format: Rachel E. Ellsworth, Craig D. Shriver. Demographic differences in African American compared to Caucasian women with luminal A breast cancer. [abstract]. In: Proceedings of the Fifth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2012 Oct 27-30; San Diego, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2012;21(10 Suppl):Abstract nr B49.
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