Study sheds light on racial breast cancer disparities

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While underinsured African-American patients had poorer breast cancer-specific survival than underinsured non-Hispanic white patients, adjustment for clinical and sociodemographic factors suggested the effect of race on survival was not statistically significant, according to a study published June 23 in the online Journal of the National Cancer Institute. The study also refuted earlier reports, demonstrating that African-American and non-Hispanic white women are equally likely to undergo breast-conserving procedures and adjuvant therapy.

 “The disparity in breast cancer mortality between African-American women and non-Hispanic white women has been the subject of increased scrutiny,” explained lead author Ian K. Komenaka, MD, of the department of surgery at Wishard Memorial Hospital in Indianapolis and colleagues, noting that the study was the first to look at underinsured populations of African-American and non-Hispanic white women with comparable socio-demographic profiles at a single institution.

From Jan. 1, 1997, to Feb. 28, 2006, the researchers retrospectively reviewed medical records for a total of 574 (259 non-Hispanic whites and 315 African-Americans) breast cancer patients who were treated at Wishard Memorial Hospital. Of these patients, 84 percent were underinsured.

Both patient groups had a similar average time from diagnosis to operation, adequate surgery and similar usage of adjuvant therapy and follow-up time, with average follow-up times of 80.3 months for non-Hispanic whites and 77.9 months for African-Americans. Sociodemographic characteristics were also similar in the two groups, and the authors explained that both racial groups were equally unlikely to have undergone screening mammography during the two years prior to diagnosis.

The breast cancer-specific mortality for African-Americans was determined to be 26 percent, compared with 17.5 percent for non-Hispanic whites, after accounting for the effect of comorbidities. However, the researchers found that after adjusting for age at diagnosis, clinical stage and hormone receptor status, the effect of race on breast cancer-specific survival was “no longer statistically significant.”

Moreover, African-American women are just as likely as non-Hispanic white women to undergo breast-conserving procedures and adjuvant therapy, said the researchers, noting that this finding differs from previous literature.

Noting a small patient cohort as a limitation of the study, Komenaka and colleagues hope to further their research by studying the clinical and socio-demographic factors of breast cancer patients as well as the specific cause of death to learn about causes behind racial and ethnic differences in overall survival.

“Despite the similar surgical care and adjuvant therapy, African-American women in this study had lower overall and breast cancer-specific survival compared with non-Hispanic white women. After adjustment for competing causes of death, the survival disparity between African-American and non-Hispanic white women appears to be attributable in part to differences in clinical and socio-demographic factors between the groups," wrote the researchers.  After adjustment for clinical and sociodemographic factors, however, this increased risk was reduced and no longer statistically significant, the study concluded.