African-American PSA Level Should Be Lowered

African-American PSA Level Should Be Lowered
Group Found to Have More Cancer, Same PSA

By Darcy De Leon

African-American men with prostate cancer had twice as much cancer within the prostate as white patients with the same disease characteristics, including prostate-specific antigen (PSA) level, according to results of a small study.

Researchers say the results support the argument for lowering the PSA threshold for African-American men in an effort to treat the disease in earlier stages.

Significance of results

The M. D. Anderson researchers who conducted the study are recommending that the PSA blood test threshold be lowered from 4 ng/mL (nanograms per milliliter of fluid) to 2.5 ng/mL for African-American men, says the study's principal investigator Curtis Pettaway, M.D., associate professor in M. D. Anderson's Department of Urology.

"The bottom line is that 4 is not a magic number for cancer," Pettaway says. "If you lowered the cutoff for African-American men, you would potentially diagnose cancer at a more curable stage."

Currently, a PSA of 4 or more is the point at which a biopsy is recommended to confirm that prostate cancer is present and to determine the extent of the disease.

Research methods

Researchers studied prostate specimens from 37 consecutive African-American patients with prostate cancer before and after the prostate was surgically removed (prostatectomy). They then matched the specimens with those of 35 white men of identical age, clinical stage, PSA level, biopsy strategy, year of surgery and prostate weight.

Primary results

The study found that African-American men had:

Higher Gleason scores - Gleason scores, which measure on a scale from two to 10 the cancer's aggressiveness, were greater in African-American patients.

African-American patients' Gleason scores also had nearly doubled from the time of biopsy to prostatectomy.

Gleason scores at time of biopsy were 7 or more in:

• 43% of African-American men
• 37% of white men

Gleason scores at prostatectomy were 7 or more in:

• 76% of African-American men
• 34% of white men

Tumors with greater volume - African-American patient tumors were on average 2.8 times greater in volume than white patients in this study of men with early stage disease.

Background

Previous studies show that compared to other ethnic groups, African-American men have a:

• Higher incidence of prostate cancer
• Earlier diagnosis
• Higher grade
• More advanced stage at diagnosis

As a result, African-American men are urged to begin annual prostate cancer screening [digital rectal exam (DRE) and PSA testing] at age 45 compared to 50 for other ethnic groups. Screening for African-American men with a family history of the disease should begin at age 40.

What's next?

Pettaway is planning to conduct a larger study to confirm the results and learn more about growth rates of prostate cancer in African-Americans.

"We're very excited about doing these type of studies because it tells us more about the biology of the disease," he says. "We want to learn what genetic or environmental factors lead to prostate cancer progression in African-American men."