Task force member Dr. Michael LeFevre, professor of family medicine at the University of Missouri School of Medicine in Columbia, says the impassioned backlash against the draft task force recommendation is unsurprising. "When science doesn't give us the result we want, it's pretty unusual for the medical and patient communities to turn on a dime and say, 'We were wrong,' " he told U.S. News.
The task force reviewed over 8,000 summaries of research studies related to prostate cancer screening and treatment. Many were eliminated because of major flaws. The strongest evidence came from two large trials that examined the impact of prostate cancer screening on death rates.
The first was a U.S. trial of nearly 80,000 men between the ages of 55 and 74. The men were divided into two groups: One had PSA testing and a digital rectal exam and the other had only a rectal exam. The study found that screening boosted the number of diagnosed cancers by 20 percent, but also that diagnosing the additional cancers did not reduce overall death rates over 10 years of follow-up.
The second study, involving 182,000 men and carried out in Europe, found that PSA screening reduced the number of cancer deaths by about 6 or 7 for every 10,000 men tested. Based on these results, the task force concluded, 48 men would have to be treated to prevent one prostate cancer death, exposing 47 men to the dangers of treatment.
Dr. Patrick Walsh of Johns Hopkins Hospital, a pioneer of radical prostatectomy—surgical removal of the entire prostate gland—takes issue with the task force assessment. He points to American Cancer Society statistics that show a 40 percent decrease in prostate cancer deaths since 1994, a decline that he attributes to the introduction of PSA screening.
Dr. LeFevre counters that the downward trend in prostate cancer deaths began before the PSA test was widely adopted, which suggests that the test wasn't the driving force.
Dr. Alan Wein, chief of urology at the Hospital of the University of Pennsylvania, told U.S. News in an interview that the two sides may not be as far apart as they seem. On the one hand, he says, "mortality from prostate cancer has decreased, and it happens to coincide with PSA screening. And there's no question that, before PSA screening, it was common to see people come in with metastatic or very advanced local disease. You rarely see that now. It may not be cause and effect, but those are the facts."
On the other hand, says Wein, there's also no question that too many patients are encouraged to seek radical prostatectomy or radiation and too few are informed about a third option known as watchful waiting, in which doctor and patient use periodic PSA tests, frequent physical exams, and biopsies to track a tumor's growth and decide when, if ever, to pursue aggressive treatment.
"I would hope that the whole issue helps urologists understand that we have to be forthright with patients about our expectations for treatment and those circumstances when it's most reasonable to watch and wait," Wein says.
The U.S. Preventive Services Task Force recommendation, which was made public October 11, is not final. It could change after the medical community and the public submit formal comments.