Research finds that race and ethnicity affect breast cancer mortality

April 2015

Canadian womenBreast cancer is the most common cancer and the second leading cause of death from cancer in Canadian women. However, diagnosing the disease at an earlier stage is thought to increase a woman’s chances of survival.

“One of my interests is in understanding the factors that lead to a woman being diagnosed at an earlier or later stage of breast cancer,” says Dr. Javaid Iqbal, a Master’s student supervised by Drs. Steven Narod and Paula Rochon. “Having this sort of knowledge could inform awareness and screening programs for early detection.”

Given the ethnic diversity of North America, Dr. Iqbal recently conducted a study to understand how a woman’s ethnic background influences her likelihood of being diagnosed with breast cancer at an earlier stage rather than a later stage and her risk of dying from an early stage breast cancer.

He led an observational study of more than 370,000 women diagnosed in the US with invasive breast cancer and found that there were differences in breast cancer mortality between populations. Black women were less likely to be diagnosed with early stage breast cancer compared to non-Hispanic white women. Furthermore, black women had a higher risk of death seven years after being diagnosed with stage one breast cancer compared to non-Hispanic white women and other major ethnicities.

The findings were published in the Journal of the American Medical Association and received extensive media coverage.

“The higher risk of death from early stage breast cancer among black women is probably not related to screening trends,” says Dr. Iqbal. “Differences in tumour characteristics explain some of these findings, but factors like genetics, lifestyle and diet can also play a role in the disparities among the ethnic groups. We need to do more research in this area to tease out the causes of these differences.”

Dr. Iqbal hopes that his findings will increase breast cancer awareness and access to quality care among high-risk women.

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