Black women with the most common form of early breast cancer had worse outcomes than white women even after receiving equivalent care, according to a major new study led by Loyola Medicine medical oncologist Kathy Albain, MD, FACP, FASCO.
“The study adds to an emerging body of evidence suggesting there are biological factors contributing to racial disparities in breast cancer outcomes,” Dr. Albain said. She added that researchers will be conducting additional studies on tumour samples donated by patients enrolled in the trial.
Dr. Albain is among the nation’s leading breast cancer researchers. She is the Huizenga Family Endowed Chair in Oncology Research and a professor in the department of medicine, division of hematology/oncology, of Loyola University Chicago Stritch School of Medicine.
Dr. Albain and colleagues evaluated data from the TAILORx clinical trial, which included more than 10,000 women with hormone receptor-positive, HER2-negative breast cancer that had not spread to lymph nodes. The study found that after nine years of follow-up, 83.1 percent of white women were alive with no recurrence of invasive breast cancer. By comparison, only 78.9 percent of black women were alive and cancer-free. Hispanic women had a prognosis similar to or better than that of non-Hispanic women.
Dr. Albain was a main author of the initial report of the TAILORx trial, which found that the 21-gene test could enable most patients with the most common type of early breast cancer to safely forgo chemotherapy. That study found that women whose tumours had mid-range recurrence scores did not need or benefit from chemotherapy.
An important result of this new study is that women of all races and ethnicities, when analyzed separately, could safely avoid chemotherapy. The current study found that the type and duration of chemotherapy and hormone therapy treatments were similar among black and white women and other races as well as between Hispanic and non-Hispanic women. Pathologic characteristics of the tumours were no different as well.
There also were no significant differences between black and white women in their tumour’s “recurrence score,” a measure of how likely the cancer will recur in distant organs. The score, which ranges from 0 to 100, is based on a test of 21 genes from a patient’s tumour.
“The racial disparities observed in this trial were not explained by differences in recurrence score or reported duration of antihormonal endocrine therapy,” Dr. Albain said. “Nor were the differences explained by the type of chemotherapy (if used) or characteristics such as age, tumour size or grade. As such, our results suggest that biological differences may contribute to the significantly different outcomes of black women compared to others with breast cancer.”