Background: Poor survival among African American patients with breast cancer has been attributed to low socioeconomic status and lack of access to health care. However, Hispanics of equivalent socioeconomic status and health care access exhibit much higher survival rates, almost comparable to whites. This suggests that biologic differences play a role in differences in breast cancer survival in addition to socioeconomic and health care access factors.
Methods: The authors studied clinical and molecular differences between patients with breast cancer of different ethnicity to determine biologic explanations for the observed differences in survival. Consecutive patients scheduled for breast biopsies were identified preoperatively and were interviewed. Blood was withdrawn for serum marker measurements, and tumor specimens collected at frozen section diagnosis were analyzed by flow cytometry, hormone receptor concentration, tumor grade, and Ki-67 nuclear antigen, HER-2/neu, and epidermal growth factor oncoprotein expression.
Results: Age, age at menarche, number of lymph nodes with metastasis, estrogen and progesterone receptor levels, ploidy status, S-phase, Ki-67, HER-2/neu expression, tumor grade, epidermal growth factor receptor expression, lipid-associated sialic acid (LASA), and carcinoembryonic antigen level were not significantly related to ethnicity. African Americans presented at a significantly more advanced stage and with significantly larger tumors. They were significantly heavier and had a significantly higher mean Quetelet's index and a significantly higher number of pregnancies and number of live births. Whites and Hispanics were significantly older at menopause.
Conclusions: The molecular indices associated with breast cancer prognosis do not differ significantly among whites, African Americans, and Hispanics, suggesting that the reported differences in survival among these groups are not due to biologic differences in breast cancer among ethnic groups.