Study Uncovers Disparity in Treatment Patterns in Women With Breast Cancer

A new population-based study is suggesting that there are significant racial disparities in gene expression profiling testing in women with breast cancer. The study raises the spectrum that disparities in access to innovative cancer care technologies may be further exacerbating existing disparities in breast cancer outcomes.

Researchers at Yale University report in the March issue of Journal of the National Comprehensive Cancer Network that gene expression profiling tests are readily available, but white women with breast cancer appear to be far more likely to receive a particular test known as the Oncotype Dx (ODx) when compared to black or Hispanic women with the same diagnosis.

“Observed racial and ethnic disparities in Oncotype DX testing are particularly concerning given its potential to guide treatment decisions for women with early-stage breast cancer. Unequal access to genetic testing has the potential to further exacerbate disparities in treatment quality, survival, and quality of life,” said lead study author Cary Gross, MD, Yale University School of Medicine and a member of Yale Cancer Center, New Haven, Connecticut.

The study is notable for several reasons. It examined racial disparities through a statewide, population-based analysis and identified the use of ODx among women for whom the National Comprehensive Cancer Network (NCCN) Clinical Practice Guidelines in Oncology (NCCN Guidelines) recommend it. The study also separately looked at women for whom NCCN Guidelines did not recommend testing. 

This retrospective investigation included 8,784 patients diagnosed with breast cancer in Connecticut from 2011 through 2013. The researchers analyzed the association between race, ethnicity, and ODx receipt among women with hormone receptor-positive breast cancer. Among the study population, more than 80% of the patients were white, 6.3% were black, and 7.4% were Hispanic.  

The study found that for the NCCN Guidelines-recommended group, white patients were more likely to receive ODx testing (51.4% vs 44.6% for black women and 47.7% for Hispanic women). Even after further adjusting for tumor and clinical characteristics, researchers observed significantly lower ODx use among black and Hispanic women compared with white women in the recommended group.

There was significant testing variation between the white, black, and Hispanic patients in the non-Guidelines-recommended group (21.2% vs 9% for black women and 9.7% for Hispanic women). After adjusting for tumor and clinical characteristics, the investigators observed significantly lower ODx use among black women (odds ratio [OR], 0.64) and Hispanic women (OR, 0.59) compared with white women in the recommended group. The trend was similar in the guideline-discordant group (black women: OR, 0.39 and Hispanic women: OR, 0.44).

Gross said understanding and mitigating racial barriers to gene expression testing in women with breast cancer is imperative and policymakers must ensure that there is access for all patients who need it, regardless of the color of their skin or their income.