Lower white blood cell counts in African-American women with early-stage breast cancer can lead to delays in treatment when compared with Caucasian women with the same stage of disease, according to a new study by physician-scientists at Columbia Presbyterian Medical Center at New York-Presbyterian Hospital. The treatment delays may explain racial differences in breast cancer survival, suggest the authors of the study.

Dr. Hershman and her colleagues studied 73 African-American and 126 Caucasian women, and of these women, they treated 43 African-American and 93 Caucasian women with chemotherapy. Confirming earlier research, the study found that African-American women had white blood cell counts that are on average 25 to 40 percent lower than those of women of European ancestry. The study found that these African-American women required a comparatively longer treatment duration (19 weeks versus 15 weeks).

"This difference in dose intensity may contribute to the observed disparities in survival between African-American women and Caucasian women with breast cancer," the researchers' report. Research has shown that risk of death for African-American women is 67 percent higher than for Caucasian women.

"The reasons for this disparity are probably several, including socioeconomic and biologic. However, our research points to a treatment-related factor that affects the duration of chemotherapy administration. Ultimately, this can be corrected," continued the researchers' report.