By Ann Miller Baker
When it comes to prostate cancer, the numbers are stark. Of all racial and ethnic groups, black men are the most likely to be diagnosed with prostate cancer. And they are twice as likely to die from prostate cancer as white men. Researching why these disparities exist and what to do about them has been a slow process, in part because minorities of all types are underrepresented in clinical trials.
Two new abstracts presented at the recent American Society of Clinical Oncology annual meeting look at the experience of black men with advanced prostate cancer and how they fared with either chemotherapy or hormone treatment, in comparison with white patients. And the news is encouraging.
For those undergoing chemotherapy for advanced prostate cancer, an analysis of pooled data from nine randomized phase III trials of more than 8,000 men shows chances of survival are as good for black men as white men. The median survival was the same in black men and white men overall (21 months), but black men had a 19 percent lower risk for death than white men when researchers adjusted for various important risk factors that affect survival.
"By pooling data across clinical trials, this study provided a unique opportunity to evaluate how race might affect prostate cancer response to treatment," said lead study author Susan Halabi, PhD, professor of biostatistics and bioinformatics at Duke University in Durham, NC. "This study underscores the importance of increasing the participation of racial minorities in clinical trials. Every patient who participates in a clinical trial contributes to improving care, and all patients should have the opportunity to receive needed therapies."
A second study looking at advanced prostate cancer patients’ response to the hormone therapy abiraterone showed that it may be more effective in black men than white. The prospective clinical trial of 100 men with metastatic castration-resistant prostate cancer demonstrated that black patients’ response to the hormone therapy was greater and longer lasting than in white men. Black men were more likely to have a decline in prostate-serum antigen (PSA) -- a sign of prostate cancer response -- and had a five-month longer median time to PSA worsening than white men (16.6 vs. 11.5 months).
This is the first prospective study to compare outcomes of abiraterone for advanced prostate cancer in black men and white men, according to lead study author Daniel George, MD, professor of medicine and surgery at Duke University in Durham, NC. "Our research underscores the importance of specifically studying genetically diverse populations and raising awareness of these results, so that everyone who can benefit from abiraterone is offered this treatment."
Moffitt Cancer Center researchers are leading several investigations into the possible genetic differences in prostate cancer related to race and ethnicity. In fact, Moffitt’s partnerships within the black community are even helping to fund disparities research through its George Edgecomb Society in hopes of reducing cancer’s inordinate burden on minorities.
Inclusive clinical trials are the key, said Julio Pow-Sang, M.D., who chairs Moffitt’s Genitourinary Oncology Department. "While the results from these studies are encouraging, we need to redouble our efforts to enroll black patients in clinical trials to confirm the findings, to collect more tissue samples and data in order to learn what the genetic differences may be. It’s necessary if we are to deliver on the promise of personalized medicine for all of our patients."