Racial discrepancies persist in breast cancer survival

Disparities in breast cancer survival rates between black and white women have not improved in the past two decades, according to a new study in the Journal of the American Medical Association.

Differences in breast cancer survival by race is a recognized problem among Medicare beneficiaries, according to researchers from Pennsylvania. Dr. Jeffrey Silber, PhD, from the Children's Hospital of Philadelphia, and colleagues investigated whether the racial disparities in breast cancer survival are attributable to differences in how women present when they seek care or in how they are treated (JAMA, July 24/31, 2013, Vol. 310:4, pp. 389-397).

Silber's group evaluated 7,375 black women 65 years and older diagnosed between 1991 and 2005 and three sets of 7,375 matched white control patients, using data from the U.S. Surveillance, Epidemiology, and End Results (SEER) Medicare database.

Black patients were matched with the white control populations based on demographics (age, year of diagnosis, and SEER site), presentation (demographic factors plus patient comorbid conditions and tumor characteristics), and treatment (presentation variables plus details of surgery, radiation therapy, and chemotherapy).

In the demographics match, the absolute difference in five-year survival was 12.9% (blacks, 55.9%; whites, 68.8%); this difference remained unchanged between 1991 and 2005. For the presentation characteristics match, the absolute difference in five-year survival was 4.4%, and for the treatment match, the absolute difference was 3.6% lower for blacks than for whites.

In the presentation match, fewer blacks received treatment (87.4% versus 91.8%), time from diagnosis to treatment was longer (29.2 versus 22.8 days), use of anthracyclines and taxols was lower (3.7% versus 5%), and breast-conserving surgery without other treatment was more frequent (8.2% versus 7.3%).

However, survival differences attributed to treatment discrepancies accounted for only 0.81% of the 12.9% difference, leading Silber's team to conclude that the disparities in breast cancer survival rates between black and white women are primarily related to how the patients present at diagnosis, rather than treatment differences.