Baseline PSA predicts risk of death from prostate cancer

Men who have a baseline PSA value of 10 or higher the first time they are tested are up to 11 times more likely to die from prostate cancer than are men with lower initial values, according to Duke University Medical Centre researchers.

Scientists say the finding, appearing early online in the journal Cancer, supports routine, early prostate-specific antigen (PSA) screening among healthy men with normal life expectancy - a practice several studies have recently questioned.

'There has been some controversy over the value of PSA screening beginning at age 40, but the data from this study strongly suggests that early screening can help us stratify patients' risk and identify those who need to be followed most closely from this younger age group. That, in turn, may help save lives,' says Judd W. Moul, MD, Professor of Urologic Surgery and Director of the Duke Prostate Centre and senior author of the paper.

Researchers used the Duke Prostate Centre database to identify 4,568 men who had PSA tests during the past 20 years and who were diagnosed with prostate cancer. Investigators tracked the patients' age and race and analysed each variable to assess any association with risk of death from prostate cancer or other causes.

The median age of the men at baseline was 65. The median baseline PSA was 4.5, and the average follow-up period was over nine years. Researchers found that 3.5 percent of the men died from prostate cancer during the study period, while more than 20 percent died from other causes.

Analysis showed that men with a baseline PSA of less than 4 had a very low risk of death from prostate cancer. Investigators also found that men with a score of 4 to 9.9 were three times more likely to die from prostate cancer than those with lower scores. And those with baseline values of greater than 10 were 11 times more likely to die from prostate cancer than were men with PSAs under 2.5.

African-American race and increasing age were also associated with a higher risk of death from prostate cancer and death from other causes.

The American Urological Association recommends all men should have a baseline PSA test at age 40. Duke researchers say the initial test value can be used to assess a man's future risk for prostate cancer.

'The most important result from our study was that baseline PSA was a future predictor of death from prostate cancer,' says Ping Tang, MD, a member of the Duke Prostate Centre and the department of urology at Guangzhou First Municipal People's Hospital, Guangdong, China, and the lead author of the study. 'It's commonly held that men over the age of 75 don't need to bother with PSA screening any longer, but this tells us that chronological age alone may not be enough. Patients need to take into account their initial baseline value, and if it's over 4, continuous screening may be beneficial.'