African-American women are more likely than all other women to die from breast cancer, and according to research presented this week at the annual meeting of the American Association for Cancer Research, doctors have gained more insight as to why that disparity exists.
For more than six years, researchers at the Kaiser Permanente Division of Research in Oakland, Calif. followed nearly 1,700 breast cancer patients who had been treated for four different subtypes of breast cancer, including luminal A, luminal B, basal-like or HER2-enriched cancer. During that period, about 500 of the patients had died, nearly 300 of them from breast cancer, researchers say.
Among them, black patients were nearly twice as likely as white patients to have died from breast cancer, regardless of the cancer subtype, findings that turn traditional thinking about black women and breast cancer on its head.
"The results seem to indicate that although African-American women are more likely to be diagnosed with less treatable subtypes of breast cancer compared with white women, it is not the only reason they have worse breast cancer mortality," said Candyce Kroenke, M.P.H., Sc.D., research scientist at Kaiser.
The Black-White difference in breast cancer survival rates has been traditionally attributed to the fact that black women are more commonly diagnosed with less treatable tumor subtypes, such as the hard-to-treat triple-negative strain. But even though triple-negative diagnoses prevailed in her study and the likelihood of black women developing the most-treatable luminal A subtype did not, Kroenke says that poor prognosis among blacks appeared consistent across the board.
"African-Americans with breast cancer appeared to have a poorer prognosis regardless of subtype," Kroenke said. "It seems from our data that the black–white breast cancer survival difference cannot be explained entirely by variable breast cancer subtype diagnosis," she went on to say.
Recent genetic profiling has suggested that not all cancer subtypes are created equal and both the tumor makeup and methods for treating them may vary by race.
Yet others maintain that factors such as poverty, silence and racial inequities -- not genetics -- are responsible for high mortality rates. Their efforts have focused less on treatment than on awareness and eliminating cultural barriers to seeking care.