While African-American women are less likely to get breast cancer than white women, they are more likely to die should they be diagnosed. A number of reasons have been proposed for this difference, including the fact that African-American women are more likely to be diagnosed at later stages with more aggressive disease.
However, disparities in treatment are also part of the story. Now a new study of breast cancer patients diagnosed under age 50 has reported that five-year survival rates are only 79% for black women compared to 90% for white women.

Reasons for black/white disparity in breast cancer survival

Significant differences in the genetic makeup of African Americans compared to non-Hispanic whites translate into differences in breast cancer susceptibility, type and outcome. The greater the degree of African heritage, the stronger these differences. For example, a progressively increasing frequency of triple-negative (ER-/PR-/HER2-) breast cancer, an aggressive form of the disease, has been found among breast cancer patients according to their degree of African ancestry. African Americans are also somewhat more likely to develop inflammatory breast cancer (IBC), which is even more aggressive.
However, the higher frequency of aggressive breast cancer types with less favorable outcomes does not completely account for lower survival among African Americans. There are well-documented differences in breast cancer treatment between African-American and white women, even among those with similar access to health insurance.
For example, older African-American women are significantly less likely than white women to receive radiotherapy after lumpectomy. Approximately 65% of African Americans compared to 74% of whites received radiation treatment after surgery in one study.
While African Americans have higher rates of aggressive disease, African-American women with less aggressive hormone receptor positive (ER+/PR+) breast cancer also have worse outcomes. While not intentional, disparities in treatment contribute to lower survival.

Latest research finds lower survival for younger black breast cancer patients

The study referenced at the beginning of this news story was designed to investigate survival rates according to black or white race in premenopausal women with breast cancer. To conduct the study, the authors used the Surveillance, Epidemiology, and End Results (SEER) database to identify women under 50 year diagnosed with invasive breast cancer from 1990 to 2009. Multiple statistical analyses were performed to determine the likelihood of survival for black and white women. The study included 162,976 women with breast cancer, of whom 126,573 were white, 20,405 were black, and 15,998 were of other ethnicities.
Five-year breast cancer-specific survival rates were found to be 90.1% for white women compared to 79.3% for black women. Risk of death decreased by 26% at five years after diagnosis in white women, compared to a decline of only 19% among black women. Among women diagnosed in their forties (aged 40 to 49 years), black women were 68% as likely to survive for five years as white women. The authors conclude that younger black breast cancer patients have worse breast cancer outcomes compared to similar aged white women. While mortality declines have occurred in both groups over time, more rapid gains have occurred in white women.