Treatments for Advanced Prostate Cancer May Work Better in Black Men

The American Society of Clinical Oncologists (ASCO) is holding their annual meeting in Chicago and there has already been some interesting presentations about men with advanced prostate cancer.  There have been two different studies showing that black men with metastatic prostate cancer may respond better to treatment than their white counterparts have been presented.   

Black men are more likely to be diagnosed with prostate cancer at a younger age, with an advanced stage, and with a higher grade. Black men are also twice as likely to die from prostate cancer than white men. Despite these facts, these two studies show that certain treatments for advanced metastatic prostate cancer may work better in black men. 

In this first study, run by Susan Halabi, PhD from Duke University, researchers analyzed data from nine different phase III clinical trials, that used chemotherapy (Docetaxel aka taxotere) and prednisone.  In total these two studies used data from more than 8,820 men of different races with mCRPC who were treated.

The analysis shows that black men have at least the same chances of survival as white men. The median survival for black men and white men was the same (21 months).  When the researchers did a further analysis, they found that black and white men with similar prognostic factors when compared, black men have a 19% lower risk of death when using chemotherapy than white men. 

The second study, the Abi Race clinical trial, evaluated 100 men with castrate resistant metastatic prostate cancer (mCRPC): 50 black men and 50 white men. During the clinical trial, all the men were treated with abiraterone acetate (Zytiga), along with prednisone until their cancer progressed or side effects forced them to stop. The researchers measured the time it took for the cancer to worsen, called progression-free survival (PFS), by using imaging scans and PSA tests.

The study’s results showed abiraterone was effective at stopping or slowing advanced prostate cancer in both black men and white men. When that effectiveness was measured by imaging scans, both groups had a median PFS of nearly 17 months. This means that the cancer had visually stopped growing and spreading on scan images during that time span.

But when PFS was evaluated using the PSA blood test, there was a difference between black men and white men. The median PFS when measured by PSA test results was nearly 17 months in black men and 11.5 months in white men.  In addition, abiraterone led to greater declines in PSA in black men than in white men. 

According to the researchers of both studies there are biological differences in what drives prostate cancer in black men and white men. Other research has shown that the way hormones therapy works in black men is different from how they work in white men, and this may help explain the different treatment effects.

These two studies show us that it is important to include black men and other underrepresented groups in prostate cancer clinical trials. The percentage of minority participants, including black people, in cancer clinical trials is often much lower than the percentage of the same people in the general population. This makes it hard to judge the effectiveness and safety of cancer treatments by race, and clearly there is a difference.

Joel T. Nowak, MA, MSW wrote this Post.  Joel is the CEO/Executive Director of Cancer ABCs.  He is a Cancer Thriver diagnosed with five primary cancers - Thyroid, Metastatic Prostate, Renal, Melanoma, and the rare cancer Appendiceal cancer.