Breast cancer survival disparities between black and white women are worsening over time, although one recent study suggests black women may be largely unaware of their increased risk.1
As part of a series of reports on “The Cancer Gap”, the New York Times has published a collection of troubling timeline graphs depicting trends in breast cancer survival since 1975 among white women and black women across the United States. The graphs show that, since 1975, ethnic disparities in breast cancer survival have become markedly worse nationwide.2
Public information and early-detection screening campaigns—as well as advances in treatment options—have yielded steady improvements in breast cancer survival rates in white women. However, the timelines show those gains have not benefitted black women nearly as much. In 1975, the breast cancer mortality rate for black women was 31.8 per 100,000 women, compared with a slightly better 29.5 per 100,000 among white women with breast cancer; by 2010, those figures were 30.9 and 22.1, respectively.2
Tennessee has seen the worst breast cancer survival disparities, the timelines show. Yet Massachusetts seems to be bucking the overall trend, with a narrowing survival gap between black and white women.2 Massachusetts passed statewide health insurance reforms in 2006, mandating insurance coverage for most residents.
The 2010 federal Affordable Care Act (ACA) includes a similar health insurance mandate, which takes effect this year. But whether or not the ACA will lead to reductions in survival disparities is still unclear.
Researchers agree that socioeconomic status (SES) and access to care are indeed important parts of the puzzle of ethnic disparities in cancer survival. However, research shows that differences in tumor biology and patient lifestyle factors are also important.
A recent analysis of the California Cancer Registry found that, when analysis is adjusted for age, breast tumor subtype, and SES, “much of the black/white disparity disappears.”3
“SES plays a prominent role in breast cancer–specific mortality but it does not fully explain the racial/ethnic disparities and continued research in genetic, societal and lifestyle factors is warranted,” the authors concluded.3
Recent genetic analyses indicate that black women with breast cancer tend to harbor more aggressive tumors than do white women. One such study found that 20 of 84 genes involved in breast carcinoma prognosis, therapy response, and tumor aggressiveness, are “differentially expressed” in white and black women.4 Black women’s tumors were significantly more likely to exhibit G(1)/S cell-cycle regulatory gene aberrations and little or no expression of estrogen pathway and ESR1, PGR, and ERBB2 targets, the authors reported.4
Breast tumors of black women are more often poorly differentiated, estrogen receptor (ER)-negative, and “exhibit a high S-phase fraction compared with tumors from white Americans,” noted American Cancer Society Chief Medical Officer Otis Brawley, MD, a leading authority on cancer disparities.5
Dietary differences, breastfeeding rates, and obesity are also factors, he believes.5
Even with the ACA mandate that all Americans secure health insurance, racial disparities in cancer and other chronic disease outcomes could well get worse—possibly much worse—in the years to come, warns Dr. Brawley. That’s partly because half of black women are now overweight or obese, he noted during his keynote speech at the 2013 American Association for Cancer Research Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved, in Atlanta, GA, on December 6, 2013.
In the years to come, obesity could even threaten to “overtake tobacco” as a leading cause of cancer and chronic disease among ethnic-minority women, Dr. Brawley said.
In addition to higher mortality rates, black women with breast cancer also suffer more frequent effects to quality of life, research suggests. Among older women with newly diagnosed with breast cancer, functional disability disproportionately affected black women compared with women of other ethnicities, according to a recent study published in the journal Cancer.6
Differences in timely chemotherapy might also be contributing to outcome disparities, suggests a recent analysis of records in the National Comprehensive Cancer Network Outcomes Database.7 For 6,622 women diagnosed with stage I to stage III breast cancer between 2003 and 2009, the time from pathologic diagnosis to initiation of chemotherapy was significantly longer for black women (median 1.5 weeks; P < 0.001) and Hispanic women (median 0.8 weeks; P < 0.001), than white women.7 Black women with Medicare insurance had longer waits for chemotherapy than did women with commercial health insurance plans, the authors noted (P < 0.001).7
“This suggests the importance of targeted efforts to minimize potentially preventable causes of delay, including inefficient transfers in care or prolonged appointment wait times,” they concluded.7
- Kaiser K, Cameron KA, Curry G, Stolley M. Black women’s awareness of breast cancer disparity and perceptions of the causes of disparity. J Community Health. 2013;38(4):766-772.
- Parker-Pope T. Tackling a racial gap in breast cancer survival. New York Times. Dec. 20, 2013. http://www.nytimes.com/2013/12/20/health/tackling-a-racial-gap-in-breast-cancer-survival.html?pagewanted=print. http://www.nytimes.com/2013/12/20/health/tackling-a-racial-gap-in-breast-cancer-survival.html?pagewanted=print. Accessed January 1, 2013.
- Parise CA, Caggiano V. Disparities in race/ethnicity and socioeconomic status: risk of mortality of breast cancer patients in the California Cancer Registry, 2000-2010. BMC Cancer. 2013;13:449.
- Grunda JM, Steg AD, He Q, et al. Differential expression of breast cancer-associated genes between stage- and age-matched tumor specimens from African- and Caucasian-American women diagnosed with breast cancer. BMC Res Notes. 2012;5:248.
- Brawley OW. Health disparities in breast cancer. Obstet Gynecol Clin North Am. 2013;40(3):513-523.
- Owusu C, Schulchter M, Koroukian SM, et al. Racial disparities in functional disability among older women with newly diagnosed nonmetastatic breast cancer. Cancer. 2013;119(21):3839-3846.
- Vandergrift JL, Niland JC, Theriault RL, et al. Time to adjuvant chemotherapy for breast cancer in National Comprehensive Cancer Network institutions. J Natl Cancer Inst. 2013;105(2):104-112.