Course of Breast Cancer Treatment Differs for Black and White Women

National Cancer Institute
Monday, 10 May 1999

Researchers from the National Cancer Institute (NCI) have found significant differences in how black and white breast cancer patients are treated during their illness. The results were reported in the April 29, 1999 issue of the journal Ethnicity and Disease.

Using a new method of analysis developed by the authors, the study confirms and adds knowledge to previous findings about the impact of socioeconomic differences on breast cancer treatment for black and white women. This method examines the first course of treatment (that is, the first three months of treatment) recommended for stage-specific diagnoses of breast cancer, rather than only individual types of treatment, such as surgery, radiation, or chemotherapy. Each woman's actual treatment was compared against the "minimum expected treatment," which was defined in the study using National Institutes of Health Consensus Conferences for each stage of diagnosis.

"It's disconcerting, as these results show, that older patients are not receiving chemotherapy, as NCI Consensus Conferences advise," said Otis W. Brawley, M.D., NCI assistant director, Office of Special Populations Research. "We need more research to determine how cancer treatment for different groups is influenced by social and economic factors. I commend the authors on developing a method that evaluates whether patients received the course of treatment advised for their stage. This sort of study should be conducted more often."

Since the distribution of nearly all characteristics were significantly different for black and white women, black and white cases were examined separately to evaluate factors most likely to be associated with early or late stage of disease at diagnosis. Income was associated with stage only for white women. For black women, who were concentrated in low-income groups, the significant predictors of late stage of disease were: no usual source of care and lack of screening. The study then examined only those breast cancer patients who were diagnosed with a later stage of disease and found that age was most strongly associated with not receiving minimum expected treatment. These older women were also likely to report having lower income, less education, public health insurance, and no usual source of health care.

When results for all diagnostic stages were combined for each race, 21 percent of black women and 15 percent of white women did not receive the minimum expected treatment. The shorter survival and higher mortality observed for black women compared to white women was attributed to a "cumulative process," whereby race was correlated with lower social class and the lack of a usual provider, less screening, later stage at diagnosis, and consequently, less likelihood of receiving the minimum expected therapy. Data were not adjusted for comorbidity. An appendix to the paper details the rationale for the expected minimum treatment for each stage of disease.

Data from NCI's Black-White Cancer Survival Study (BWCSS) were examined for this analysis. Patients in the BWCSS were diagnosed during 1985 to 1986, but this is one of the few data sets in the United States with clinical staging and medical treatment on enough black and white patients to allow analysis by race and socioeconomic status of health services differences over breast cancer diagnosis and the first course of treatment.

The BWCSS used age, race, gender, and staging data on breast cancer patients reported to local cancer registries in three metropolitan areas, then matched black patients by age to white patients. This group of black and white patients were interviewed about their income, insurance, screening, and usual source of care. Data were also obtained from medical records. Patients were between the ages of 20 and 79 years old and lived in Atlanta, New Orleans, or San Francisco.

"This study found that disparities in breast cancer diagnosis and treatment most adversely affected women who are black, or older, or poor," said lead author Nancy Breen, Ph.D., NCI Division of Cancer Control and Population Sciences, Applied Research Branch. "These data were collected in 1986, before screening for breast cancer was widespread. This raises the question of whether these same inequalities still prevail. It may be time to monitor this again."

Brawley added, "it would be useful to monitor other racial and ethnic groups in which disparities in cancer care are suspected as well. Differences in treatment, as shown in this paper, clearly contribute to racial disparities in disease outcomes."

Having health insurance facilitates access to a regular health care provider, which in turn may facilitate screening and early diagnosis, the paper notes. The health insurance situations of BWCSS participants mirrored national employee benefits studies conducted in the mid-1980s, which showed whites were more often covered by employer-based health plans than blacks. Of the under-age 65 group of women studied, 68 percent of blacks and 94 percent of whites had private health insurance; 16 percent of blacks and 3 percent of whites had public insurance; and 16 percent of blacks and 4 percent of whites had no insurance. For the 65 and older group, 50 percent of black women in the sample depended on unsupplemented public insurance compared to 8 percent of white women.

The paper, entitled "The Relationship of Socio-Economic Status and Access to Minimum Expected Therapy Among Female Breast Cancer Patients in the National Cancer Institute Black-White Cancer Survival Study," appeared in the April 29, 1999 issue of the journal Ethnicity and Disease, published by The International Society on Hypertension in Blacks. The authors are Nancy Breen, Ph.D., NCI, Margaret N. Wesley, Ph.D., Information Management Services, Inc., Silver Spring, Md., Ray M. Merrill, Ph.D., NCI, and Karen Johnson, M.D., previously with the Food and Drug Administration, and now with NCI.

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