Duke Prostate Cancer Research at ASCO

Investigators examine relationship between race and patient outcomes

Article

Researchers from the Duke Cancer Institute presented more than 40 different education sessions, oral presentations, posters, and more at the American Society of Clinical Oncology (ASCO) annual meeting, held June 1 to 5, 2018, in Chicago, Illinois. Findings from two Duke late-breaking abstracts are highlighted below.

Black Patients Show Stronger Response to Hormone Therapy for Prostate Cancer

Black men with metastatic castration-resistant prostate cancer (mCRPC) might be more responsive than white men to abiraterone acetate and prednisone, according to a prospective, multi-center study led by Duke Cancer Institute researchers.

Although median survival was similar for both black and white participants, the findings suggest that racial determinants may factor into the degree of response in patients. This difference could help drive strategies to improve outcomes in those who respond better to the drugs.

“African-Americans have a 2.5 times greater chance of dying from prostate cancer compared to whites,” says Duke medical oncologist Daniel George, MD, who presented the findings.

“Our study provides prospective evidence that there might be inherited genes that could affect treatment response and track with African ancestry in prostate cancer patients,” he said. “We need to look closely at the underlying genetic differences that associate with treatment response and build on that to improve survival for these patients.”

In the analysis, response to therapy was measured by decline in prostate-specific antigen (PSA). For black men, PSA levels declined at higher rates and remained stable for a median 16.6 months compared with 11.5 months for the white participants.

The changes in disease progression were less striking; both groups had a median time to radiographic progression of 16.8 months. Still, the authors say the study suggests a potential strategy for new therapies and hormonal treatment regimens that could narrow the prostate cancer survival disparity between blacks and whites.

Survival Benefit for Black Men with Advanced Prostate Cancer

Certain black men with mCRPC have as good a chance of survival as white men and might even have a lower risk of death, according to a new analysis of more than 8,000 patients who participated in clinical trials.

The study was presented June 1 at ASCO by lead author Susan Halabi, PhD, professor of Biostatistics and Bioinformatics and a member of the Duke Cancer Institute, who noted that the racial disparities long associated with prostate cancer are complex and persistent.

Halabi and colleagues conducted their analysis on pooled data from nine large studies that used the chemotherapy drug docetaxel. In their analysis, the investigators took into consideration patient characteristics already known to affect survival, including age, performance status such as ability to manage daily activities, PSA levels, and site of metastasis.

Although the black men in the analysis were younger and sicker, their overall median survival was nearly equal to that of the white men, at 21 months. That alone was unexpected, Halabi says, since the black men carried a heavier burden of disease. But when they compared men of different races to each other based on the key disease variables, the survival advantage for black men (19%) was even more surprising.

“These findings are specific to men who enrolled in these trials and who have been treated with docetaxel-based therapies,” Halabi says. “The results of this analysis suggest there might be biological variations in either the disease or response to treatments that should be further explored.”