I began to see that cancer’s invasiveness was deeply rooted in human conditions, and began asking questions such as: What does it mean to be black in America? What does it mean to be poor? And what does it mean to be black and poor and at the same time to have cancer? Saving lives under these conditions has dominated my career ever since.

The reasons for black and white differences in breast cancer outcomes are complex. Although the incidence of the disease is higher among white women, black women are more likely to die from it. Young black women tend to develop a particularly aggressive form, which no doubt contributes to the disparity. But for many years, the dominant cause of higher mortality has been late-stage disease at the time of initial treatment, in part as a result of black women being less likely to undergo mammography.

However, this gap has been closed. The Centers for Disease Control and Prevention reports that the rate of mammography is now the same in black and white women. What remains different is what happens after the mammogram: Black women experience significant delays in diagnosis and treatment. According to the C.D.C., even when they have similar insurance coverage, 20 percent of black women with an abnormal mammogram wait more than 60 days for a diagnosis, compared with 12 percent of white women. And 31 percent of black women wait 30 days to begin treatment, compared with 18 percent of white women.

The Institute of Medicine reported in 2003 that black Americans with health insurance similar to that of white Americans are, at times, less likely to be recommended by physicians to receive curative cancer care. I don’t think this is because doctors are racist, but rather that they make assumptions about race that can be harmful. For example, a specialist treating a poor black woman may doubt that she will comply with a complex treatment and recommend a simpler, but noncurative, therapy instead.

The good news is that studies show that black and white women who receive the same breast cancer treatment at the same stage of the disease are equally likely to survive. If we can eliminate barriers to early diagnosis and quality treatment in black women, we can close the racial mortality gap.