NEW YORK, September 14, 2010 - A blood test at the age of 60 can accurately predict the risk that a man will die from prostate cancer within the next 25 years, according to researchers at Memorial Sloan-Kettering Cancer Center, in New York, and Lund University, in Sweden. The findings, published today online in the British Medical Journal, could have important implications for determining which men should be screened after the age of 60 and which may not benefit substantially from continued prostate cancer screening.
The study analyzed blood samples from 1,167 men born in 1921 that were collected between 1981 and 1982 as part of the Malmö Preventive Project in Sweden. All men were carefully followed until they had reached age 85 or had died. After studying various biomarkers, the researchers found that the PSA level was a highly accurate predictor of long-term risk. PSA testing has been recommended for the early detection of prostate cancer for many years; however this new data suggests a baseline PSA could determine who should and should not continue to be screened for prostate cancer.
"We were hoping to find a novel marker," said lead researchers Andrew Vickers, PhD and Hans Lilja, MD PhD. "What we found instead was a new way of using an old test."
According to the study, 126 men were diagnosed with prostate cancer, and of those, 90 percent of deaths occurred in men in the top 25 percent of PSA levels at age 60. The researchers concluded that men with a PSA level above 2 ng/ml at age 60 should be considered at increased risk of aggressive prostate cancer and should continue to be screened regularly.
Men with a PSA level below 1 ng / ml had a 0.2 percent chance of death from prostate cancer. The researchers concluded that men with PSA levels in this range, which is about half of all men, should be considered at low risk of prostate cancer death and may not need to be screened in the future. The study also indicated that some men found to be at low risk may actually have prostate cancer; however it is not likely to cause symptoms or shorten their life by the age of 85.
"This is a key finding," said Dr. Vickers. "We know that screening detects many prostate cancers that are not harmful, leading to anxiety and unnecessary treatment. It is our ability to determine the risk of the really aggressive cancers that makes this approach of such great potential value."