Racial differences in breast cancer diagnosis and initial course of therapy Free

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Background: There is growing evidence that breast cancer diagnosis differs by race, and these differences may in part explain racial differences in prognosis.
 >Methods: The Pathways Study is a prospective study of breast cancer prognosis being conducted in Kaiser Permanente Northern California. With ongoing enrollment since January, 2006, over 1,300 women have been enrolled in the study. The analyses presented here include 691 study participants who were also listed in the KPNC Cancer Registry (updated through March, 2007), the source of diagnostic detail.
 >Results: Among the 691 study participants, 48 (7.0%) were African American, 73 (10.7%) were Asian, 65 (9.5%) were Latina, and 496 (72.4%) were White. African American women were substantially more likely to be diagnosed with tumors that were estrogen-receptor negative (39.1%, compared to 23.4% for Latina, 14.1% for Asian, and 12.9% for White women), and progesterone-receptor negative (51.1%, compared to 30.4% for Latina, 23.9% for Asian, and 27.8% for White women). Her-2-neu marker status differed much less markedly by race/ethnicity (negative status for 79.1% of African American women, compared to 75.9% for Latina, 74.6% for Asian, and 73.7% for White women). The proportion of women who were negative for ER, PR and her-2-neu marker status was substantially higher for African Americans than others (32.6%, compared to 14% for Latina, 3% for Asian, and 7.4% for White women). A higher proportion of African Americans were likely to begin chemotherapy (61.7%, compared to 55.6% for Latina, 51.4% for Asian, and 38.1% for White women), and a lower proportion to receive hormone therapy (24.4%, compared to 35% for Latina, 40.3% for Asian, and 46.9% for White women). Although the proportions of women who were negative for ER, PR or Her-2-neu marker status decreased with increasing age, age did not account for racial differences in diagnosis. BMI and menopausal status also did not appear to account for these racial differences in diagnosis.
 >Conclusions: These results confirm other observations of substantial racial differences in breast cancer diagnosis. Higher proportions of breast cancers that are negative for hormone receptor status result in fewer effective conventional treatment options. Interactions of these tumor characteristics with other genetic and lifestyle factors will provide insight into explanations for racial differences in breast cancer prognosis.
 >Supported in part by grants R01 CA105274 from the National Cancer Institute and BC043120 from the Department of Defense.