More men will have been diagnosed with prostate cancer than any other cancer in 2005 and more than 30,000 men will have died from the disease, according to background information in the article. Men can be screened for prostate cancer by measuring prostate-specific antigen (PSA) levels in the blood and performing digital rectal examination. However, there is little evidence of these tests' effectiveness in reducing death, the authors report. In this context, medical groups differ on screening guidelines; for instance, the American Cancer Society states that doctors should offer the PSA blood test and digital rectal exam annually to men age 50 years or older, whereas the U.S. Preventive Services Task Force has found insufficient evidence to recommend screening and the American College of Physicians advises physicians to counsel men about its benefits and risks.
John Concato, M.D., M.P.H., from the Veterans Affairs (VA) Connecticut Healthcare System, West Haven, and Yale University, New Haven, and colleagues conducted a study to address the question of whether screening improves the chances of survival. From approximately 72,000 veterans receiving health care at any of 10 VA medical centers in New England, they identified 501 men age 50 years and older who were diagnosed with prostate cancer between 1991 and 1995 and had died by the end of 1999. A comparison group of 501 living men was also identified; each man in this control group was matched, for age and treatment at the same center, to a man with prostate cancer who had died. Medical records were reviewed to determine whether men in either group had been screened for prostate cancer.
Seventy--or 14 percent--of the men who died of prostate cancer and 65 (13 percent) of the men in the control group were screened with PSA. If prostate cancer screening prevented death, fewer men who died would have received screening compared to the men who were living, the authors report. In addition, screening was not found to reduce mortality among men who were younger or healthier or when digital rectal exams were also considered. According to the authors, screening tests can increase the detection of cancer, even at earlier stages, but not necessarily prolong survival.
"Optimal clinical strategies for diagnosing and treating prostate cancer remain uncertain and in need of additional investigation," they write. "Based on available evidence, including the present study, recommendations regarding screening for prostate cancer should not endorse routine testing of asymptomatic men to reduce mortality. Rather, the uncertainty of screening should be explained to patients in a process of 'verbal informed consent,' promoting informed decision making."
(Arch Intern Med. 2006; 166: 38-43. Available pre-embargo to media at www.jamamedia.org.)
Editor's Note: This research was supported by grant funding from the Department of Veterans Affairs.
Editorial: More Studies Needed to Solve PSA Conundrum
In an accompanying editorial, Michael J. Barry, M.D., from Massachusetts General Hospital, Boston, comments on the uncertainty regarding prostate cancer screening.
"We already know that PSA screening has a substantial downside," Dr. Barry writes. "The poor specificity of PSA testing results in a high probability of false positives requiring prostate biopsies and lingering uncertainty about prostate cancer risk, even with initially negative biopsy findings." Aggressive treatment also can cause incontinence and sexual dysfunction in men, he reports.
"The key question is whether early detection and subsequent aggressive treatment of prostate cancers found through PSA screening prevents enough morbidity and mortality to overcome these disadvantages--it will have to work to some degree just to 'break even'," he writes. Additional studies are needed to determine if the benefits outweigh the risks for most men.
(Arch Intern Med. 2006; 166: 7-8. Available pre-embargo to the media at www.jamamedia.org.)