Feb. 15, 2010 -- Men with a PSA (prostate-specific antigen) level of less than 1 nanogram per liter of blood can safely wait up to eight years between PSA screenings, researchers say.
And men with PSA levels of less than 3 at the time of the first screening test do not need biopsies to check for prostate cancer, says Monique Roobol, PhD, an epidemiologist in the department of urology at Erasmus University Medical Center in the Netherlands.
Roobol and colleagues studied more than 40,000 men aged 55 and 74, about 15,000 of whom had PSA levels less than 3. Over an 11-year period, 915 of the men developed prostate cancer and 23 died of the disease.
"Their overall risk of prostate cancer death was low -- 3.5-fold lower than [in the general] population," Roobol tells WebMD.
Men with levels less than 1 fared the best: Only three of the 7,126 men with levels below 1 died of prostate cancer vs. nine of the 2,476 men with PSA levels between 2 and 2.9.
"The favorable outcome in men with initial PSA values of less than 1 supports prolongation of the screening interval up to eight years," she says.
The study also showed that men with an initial PSA of 3 or greater were 11 times more likely to have aggressive cancers or die from prostate cancer than those with lower levels.
Commenting on the findings,Nicholas J. Vogelzang, MD, chair and medical director of the developmental therapeutics committee of US Oncology, says, "I believe this study gives us some confidence that annual PSA screening is going to soon become a thing of the past. A low PSA, especially those in men with levels less than 1, and probably less than 2, certainly could be considered for substantially longer intervals of PSA screening."
Also, "we formerly learned that men with PSA levels of 4 and greater should undergo biopsy. These findings suggest that that number should drop to 3," he tells WebMD.
But Neil Fleshner, MD, of the University Health Network in Toronto, says, "I think PSA screening is here to stay. It is my personal thinking that perhaps use of PSA in younger men may be better than in older men."
Additionally, many more biomarkers that will be helpful in finding aggressive prostate cancers will be discovered in the next few years, Fleshner predicts.
The findings were released at a press briefing held in advance of the Genitourinary Cancers Symposium in Orlando, Fla., later this week.
Also at the meeting, Fleshner reported that a widely prescribed drug used to shrink enlarged prostates appears to reduce the risk of progression of prostate cancer in low-risk men.