Black women are significantly more likely to die from breast cancer compared to white women after being diagnosed, new research finds.
"This difference was greatest in the first three years after diagnosis," study author Erica Warner, a postdoctoral fellow at Harvard School of Public Health in Boston, Mass., said in a press release.
The study, presented this week at an American Association for Cancer Research conference in Boston, involved 19,480 women who were treated for stage one to three breast cancer between January 2000 and December 2007. The researchers looked for breast cancer deaths among 634 Asian women, 1,291 Hispanic women, 1,500 non-Hispanic black women and 16,055 non-Hispanic white women.
After following-up with patients for an average of about seven years, the researchers determined non-Hispanic black women had almost a 50 percent higher risk for breast cancer death in the first three years following diagnosis compared with non-Hispanic white women. A black woman with estrogen-receptor-positive type breast cancer doubled her risk of dying within the first three years of diagnosis compared to a white woman. Death risk was also higher in black women with luminal A and luminal B breast cancer subtypes compared to their white counterparts.
"This finding is important because these are the types of tumors that we traditionally think of as more treatable," Warner said.
After the three-year-period from first being diagnosed, the risk for dying of breast cancer in black women dropped to 34 percent.
There was no difference in death risk between black and white women for estrogen receptor-negative, basal or HER2-overexpressing tumor subtypes of breast cancer.
The study backs prior research that finds major racial disparities when it comes to breast cancer survival.
The study also found Asian women were 40 percent less likely to die from breast cancer compared with white women for all types of breast cancers. There was no significant risk difference found between Hispanic women and white women.
The results are considered preliminary since they were presented at a medical conference and not yet published in a peer-reviewed journal.
"The results of this study emphasize that clinical management and follow-up for patients with breast cancer, particularly black women, is important in the first few years after diagnosis," Warner said. "Although the difference between blacks and whites was highest for this time period, the risk for death was highest in the first few years after diagnosis for all groups."
Warner wasn't sure what created the differences since the team's research model accounted for many factors that might influence survival, including age and tumor features.
"We thought it might have something to do with treatment differences, but we accounted for disparities and the differences persisted," she explained to WebMD.
She did note that on average, black women in the study were diagnosed at a later stage of breast cancer. She also said body mass index (BMI) played a role in survival, with death risk differences seen at a BMI of 25 (overweight) and 30 and higher (obese).
About 226,870 new cases of invasive breast cancer will be diagnosed in women in 2012, according to the American Cancer Society, along with 63,000 cases of carcinoma in situ (CIS, non-invasive). More than 39,500 women are expected to die from the disease this year.