Wayne State School of Medicine researcher finds that prostate cancer grows faster and more aggressively in black men

April 8, 2010

Prostate cancer grows more rapidly and becomes more aggressive earlier in black men than in white men, a study by a team of Wayne State University School of Medicine researchers has determined.

The study, "Evidence Supports a Faster Growth Rate and/or Earlier Transformation to Clinically Significant Prostate Cancer in Black Than in White American Men and Influences Racial Progression and Mortality Disparity," was published online in The Journal of Urology.

"The evidence is growing that there are distinct genetic differences between Americans of European descent and Americans of African descent when it comes to how prostate cancer affects the two groups," said Isaac Powell, M.D., of the Wayne State University Physician Group and professor of Urology at the Wayne State University School of Medicine and Karmanos Cancer Institute.

He noted that traditionally recognized disparities -- the lack of primary medical care access for American blacks -- did not play measurably significant roles in the differences discovered in his study. However, treatment decisions, high blood pressure and obesity may be partly responsible for prostate cancer outcome disparities.

One of every three cancer diagnoses in males in the United States involves the prostate. The U.S. Centers for Disease Control reported that in 2004, men with a primary diagnosis of prostate cancer were the second-largest group of cancer survivors nationwide. At the beginning of 2003, an estimated 81,417 prostate cancer survivors were living in Michigan. An additional 8,540 men in the state were diagnosed with new cases of prostate cancer in 2004.

If found and treated early, prostate cancer can be cured. Nevertheless, prostate cancer is a leading killer in Michigan and the nation, with the death rate for black men twice that of white men. Similarly, black men are 1.6 times more likely to be diagnosed with the disease than white men.

Dr. Powell and his co-researchers evaluated prostate glands from autopsies of 1,056 black and white men who died of causes other than prostate cancer. They also reviewed data from their radical prostatectomy database and from the Detroit Surveillance, Epidemiology and End Results, a cancer registry. In the prostate cancer autopsy study of patients who died from other causes, the cancers were mostly small and considered latent or insignificant cancers that don't progress and cause problems. The data showed that prostate cancer in those patients between the ages of 20 and 60 behaved no differently from one patient to another regardless of race.

Among those who underwent radical prostatectomy for significant progressive disease -- the surgical removal of a cancerous prostate gland and the surrounding tissue -- post-surgical cancer volume was greater in black than in white men. The percentage of men diagnosed with metastatic disease (cancer that spread to distant sites) was three times greater among black men compared to white men.

The study also suggested that black men diagnosed with prostate cancer may require more treatment for longer periods of time if not diagnosed early.

While Dr. Powell said that all men above age 40 should increase their awareness of prostate cancer and discuss baseline screening with their doctor, black men should begin screening earlier than the current American Cancer Society or American Urology Association recommendations. "I believe black men should begin that testing at age 35," he said. "The study shows that these patients need a five-year lead time to decrease mortality rate disparity should they be diagnosed with prostate cancer."

Cathryn Bock, Ph.D., M.P.H., assistant professor of the WSU Department of Internal Medicine and the Division of Hematology/Oncology and the Karmanos Cancer Institute; Julie J. Ruterbusch, research assistant; and Wael Sakr, M.D., Chair and professor of the Wayne State University Department of Pathology and the Karmanos Cancer Institute, conducted the study with Dr. Powell.

Wayne State University is a premier urban research university offering more than 350 academic programs through 13 schools and colleges to nearly 32,000 students.