Women with aggressive breast cancer at diagnosis were more likely to receive chemotherapy, but at the expense of completing locoregional radiotherapy, according to data presented at the Fifth American Association for Cancer Research (AACR) Conference on The Science of Cancer Health Disparities in San Diego Oct. 27—30.

“This disproportionately affects minority patients and results in underuse of radiation in these women,” wrote Abigail Silva, MPH, of the University of Illinois in Chicago, and colleagues in the study’s abstract. Minorities are more likely to present with moderate-to high-grade and symptomatically detected tumors, they explained.

Prior studies have shown that black and Hispanic women are less likely than white women to obtain radiation treatment when eligible, and this may partly explain racial/ethnic disparities in breast cancer outcomes, according to Silva.

In an effort to better understand the causes of disparities in radiation treatment, the researchers gathered interview and medical record data from a population-based study of 989 breast cancer patients—397 non-Hispanic whites, 411 non-Hispanic blacks and 181 Hispanics.

Among eligible patients who consented to medical record abstraction and had a single invasive primary tumor, 88 percent were recommended for radiotherapy. Of those, 93 percent accepted. Factoring in the 3 percent that accepted but did not actually receive treatment, the final tally was 79 percent of the initial population that actually initiated treatment.

Minority patients were less likely than non-Hispanic white patients to initiate radiation, reported Silva and colleagues, with treatment rates of 75 percent and 85 percent, respectively.

In addition to the finding that minorities were more likely to present with higher grade tumors, they also were more likely to receive chemotherapy, both factors associated with lower receipt of radiotherapy.

The researchers said the results indicate clinicians may not be recommending guideline-concordant radiation treatment to all eligible patients. “Indeed, we found that once a treatment recommendation was made, the vast majority of patients received treatment," Silva said in a press release. "In addition, greater diffusion of gene expression profiling may improve cancer care, not only by reducing overuse of chemotherapy but by eliminating chemotherapy as a potential barrier to receipt of radiation."

Radiation treatment decreases the risk of breast cancer recurrence and improves survival, according to Silva.