Blurring The Racial Lines On Prostate Cancer

Susan Halabi, PhD, presented her findings at the 2018 ASCO Annual Meeting An increased survival benefit for African-American men with advanced prostate cancer and a stronger response to hormone therapy were the centerpieces of key racial disparity studies presented by researchers from Duke’s Prostate & Urologic Cancer Center at the 2018 American Society of Clinical Oncology (ASCO) Annual Meeting.

African-American men are underrepresented in clinical trials for prostate cancer, despite an almost two-fold greater incidence and mortality of disease in African-American vs white populations.

In a study led by Susan Halabi, PhD, researchers pooled data from nine randomized phase III trials of more than 8,000 men with advanced prostate cancer who received chemotherapy. Surprisingly, the results showed that chances of survival are as good for African-American men as for white men on clinical trials. While the median survival was the same (21 months), African-American men had a 19 percent lower risk for death than their white counterparts when adjusting for important variables.

“By pooling data across clinical trials, this study provided a unique opportunity to evaluate how race might affect prostate cancer survival and response to treatment,” said Halabi.  “The results of this analysis suggest there might be biological variations associated with race in either the disease or response to treatments that need to be further explored. Our study highlights the importance of minority groups participating in medical studies.”

Daniel George, MD, presenting his AbiRace findings at the ASCO 2018 Press ConferenceSimilarly, in a prospective, multi-site study led by Daniel George, MD, researchers enrolled equal numbers black and white men with metastatic, resistant prostate cancer who were treated with the anti-hormone therapy, abiraterone, and the steroid, prednisone. African-American men had a greater response to therapy, characterized by more dramatic declines in a tumor blood marker called prostate-serum antigen (PSA) and had a longer median time to PSA progression than white men (16.6 vs 11.5 months).

“In this setting we demonstrated that African-American men may be more responsive to specific hormonal intervention,” said George.” “There is an urgent need explore the underlying genetic differences associated with treatment response.”

Duke researchers believe the study suggests a potential strategy for new therapies and hormonal treatment plans that could narrow the disparity between survival rates for blacks and whites in prostate cancer.

In North Carolina, the rate of prostate cancer-related deaths among African-Americans is higher than the national average. Researchers at the Duke Prostate & Urologic Cancer Center have a particular incentive to address these disparities because African-American men make up more than 25 percent of the Center’s patient population (compared to the national average of 12.4 percent).

“These two independent studies suggest that African-American men with prostate cancer can benefit the same or even more than white patients to drug treatments,” explained George. “We could close the gap in outcomes by race simply by using these widely available therapies in African-American patients on a more routine basis.”

To learn more about prostate cancer disparity research at Duke, visit our research homepage.