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.
Annual Screening May Not Be Needed
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.
In a trial involving more than 300 men with early-stage prostate cancer, those who took the drug Avodart had a 40% lower risk of having their cancer get worse, compared to men who took a placebo.
"Among men randomized to placebo, about 23% had no evidence of cancer at final biopsy [three years after entering the study]. But among men on Avodart, it went up to 36%," he tells WebMD.
All the men in the study had opted for active surveillance, also called watchful waiting. It involves regularly monitoring men with early-stage prostate cancer to determine if the cancer is growing and needs treatment.
Vogelzang tells WebMD that many men who opt for active surveillance experience high levels of anxiety, even though research has shown that their prostate cancer is so slow-growing it will probably never kill them.
Studies like this and another showing "PSA drops about 50% with this drug are gratifying to most (prostate cancer) patients. They breathe a sigh of relief," he says.
Even so, Avodart is not likely to be approved by the FDA for this use, Fleshner says.
In another study, researchers who examined the outcomes of nearly 3,800 robotic-assisted laparoscopic radical prostatectomy (RALP) operations performed by three skilled surgeons report that it took more than 1,600 procedures for the surgeons to become proficient.
Introduced in 2000, RALP provides surgeons with three-dimensional vision, improved magnification, hand tremor filtering, and a range of motion similar to the human wrist.
The procedure has caught on quickly: Of the 90,000 surgeries to remove the prostate performed each year in the U.S., about 80% are done robotically.
"This study suggests robotic prostate surgery should be limited to a few centers of excellence, and not every community hospital or every surgeon should be doing the procedures," says researcher Prasanna Sooriakumaran, MD, PhD, a visiting fellow in urology at the Weill Cornell Medical College in New York.
More than 70% of RALPs in the U.S. are performed by surgeons who do fewer than 100 cases a year, he says.
These findings were presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.