Racial disparity in breast cancer explained

High blood pressure accounts for some of the disproportionately higher mortality rates among African American women with breast cancer compared with their Caucasian counterparts, according to an article in the International Journal of Cancer.

To examine coexisting conditions that may be involved in this disparity, Dr. Dejana Braithwaite at the University of California, San Francisco, and co-investigators analyzed data for women with invasive breast cancer treated at Kaiser Permanente in Northern California between 1973 and 1986 and followed through 1999. There were 416 African-American patients and 838 white patients.

During an average follow-up of 8.9 years, the overall mortality was 39.7 percent among the black women and 33.3 percent among the white women. The corresponding breast cancer mortality was 28.6 percent and 21.6 percent African-Americans also had higher rates of hypertension (43.3 percent vs 28.3 percent.)

After controlling for tumor characteristics, breast cancer treatment, age, and race, hypertension was significantly associated with mortality from any cause. This one factor explained 30.3 percent of racial disparity in all-cause survival," as well as 20.0 percent of the racial disparity in breast cancer-specific survival, Braithwaite s group reports.

The investigators add, "our results nevertheless suggest that hypertension is an important comorbidity to consider in the context of research on racial disparity in breast cancer and our findings warrant its inclusion in comorbidity measures like the Charlson Comorbidity Index."

Furthermore, "better management of hypertension has potential to improve patient outcomes, particularly among African-American breast cancer patients," Braithwaite comments in a UCSF statement.

SOURCE: International Journal of Cancer, March 1, 2009.