A new study published early online in CANCER, a peer-reviewed journal of the American Cancer Society, shows that women of colour and young women may face elevated risks of developing triple-negative breast cancers, which are often aggressive and do not respond to hormone therapy or targeted therapy.

Previous U.S. studies have found racial disparities in triple-negative breast cancer diagnoses, but few have looked beyond the scope of one state.

To conduct a larger study, Lia Scott, PhD, MPH, of the Georgia State University School of Public Health, and her colleagues analysed all breast cancer cases diagnosed during 2010-2014 from the United States Cancer Statistics database, a population-based surveillance system of cancer registries with data representing 99 percent of the U.S. population.

The team identified 1,151,724 cases of breast cancer from 2010-2014, with triple-negative cases accounting for approximately 8.4 percent of all cases.

The researchers uncovered a significant burden of triple-negative breast cancer for women of colour, specifically non-Hispanic black women, and for younger women.

Compared with non-Hispanic white women, non-Hispanic black women and Hispanic women had 2.3-times and 1.2-times higher odds of being diagnosed with triple-negative breast cancer, respectively.

More than 21 percent of non-Hispanic black women were diagnosed with triple-negative breast cancer, compared with less than 11 percent for all other types of breast cancer.

Women younger than 40 years of age had twice the odds of being diagnosed with triple-negative breast cancer than women aged 50-64 years.

Also, among women who were diagnosed with breast cancer, those diagnosed at late stages were 69 percent more likely to have triple-negative cancer than other types.

The authors noted that due to the aggressive nature of triple-negative breast cancer and the lack of therapeutic options, it is important to know which individuals face a higher risk and what factors may influence this risk.

"With the advent and availability of more comprehensive cancer data, such as the United States Cancer Statistics database, it is important that we continue to explore disparities in order to better inform practice and policy around screenable cancers like breast cancer," said Dr. Scott.

"We hope that this update on the epidemiology of triple-negative breast cancer can provide a basis to further explore contributing factors in future research."

Source: Wiley