A US national health advisory panel is recommending against using a common prostate cancer screening test in healthy men, a finding that many cancer experts specializing in the treatment of prostate cancer view as misguided.
The United States Preventive Services Task Force (USPSTF) reviewed data from five screening trials and concluded that prostate-specific antigen (PSA) testing, a widely used screening method, ?results in small or no reduction in prostate cancer?specific mortality and is associated with harms related to subsequent evaluation and treatments, some of which may be unnecessary.?
The review was performed to update the 2002 and 2008 U.S. Preventive Services Task Force evidence reviews on screening and treatments for prostate cancer. The complete report has been published ahead of print on the Annals of Internal Medicine’s website.
Conflicting results
The panel concluded that of the five screening trials, the two largest and highest-quality studies reported conflicting results. One of these studies found screening was associated with reduced prostate cancer?specific mortality compared with no screening in a subgroup of men age 55 to 69 years after 9 years (relative risk, 0.80 [95% CI, 0.65 to 0.98]; absolute risk reduction, 0.07 percentage point). The other found no statistically significant effect after 10 years (relative risk, 1.1 [CI, 0.80 to 1.5]).
False-positive
The panel reported that after 3 or 4 screening rounds, 12% to 13% of screened men had false-positive results. The reviewers also observed serious infections or urinary retention occurred after 0.5% to 1.0% of prostate biopsies. There were 3 randomized trials and 23 cohort studies of treatments. One good-quality trial found that prostatectomy for localized prostate cancer decreased risk for prostate cancer?specific mortality compared with watchful waiting through 13 years of follow-up (relative risk, 0.62 [CI, 0.44 to 0.87]; absolute risk reduction, 6.1%).
Benefit of screening
Results of the studies reviewed seem to suggest that the benefits of prostate cancer screening test in healthy men appeared limited to men younger than 65 years of age. Treating approximately 3 men with prostatectomy or 7 men with radiation therapy instead of watchful waiting would each result in 1 additional case of erectile dysfunction. Treating approximately 5 men with prostatectomy would result in 1 additional case of urinary incontinence. Prostatectomy was associated with perioperative death (about 0.5%) and cardiovascular events (0.6% to 3%), and radiation therapy was associated with bowel dysfunction.
Sending the wrong message?
?This is the wrong message at this point in time,? says Philip Kantoff, MD, director of Dana-Farber’s Lank Center for Genitourinary Oncology. ?The issues of PSA-based screening and treatment of early disease are complex. Multiple steps and multiple decision points are involved. The blanket statement of saying that PSA-based screening is of no value is the wrong message right now. Not every man should be screened and not every man who is diagnosed with prostate cancer needs to be treated. Finding those who may benefit from screening and treatment is our focus.?
A common cancer
Prostate cancer is the most commonly diagnosed cancer, and second leading cause of cancer deaths, in men in the U.S. The American Cancer Society(ACS)estimates that more than 240,000 cases of prostate cancer will be diagnosed in the U.S. this year and that the disease will cause nearly 34,000 deaths.
Although there are no national guidelines that recommend routine PSA screening, it is commonly used in men age 50 and older as part of their annual health physicals.
Experts agree – screening not without limitations
Kantoff says that PSA screening is not without its limitations. There are issues associated with the test?s sensitivity and specificity ? as measured by the likelihood of a false negative or false positive finding ? but he views the test as a useful screening tool when used appropriately.
Selective screening
?There is no question that we need to be more careful with whom we screen, and we need to recognize that not every man needs to be screened,? says Kantoff. Furthermore, he added, it is important to know when to stop screening, such as for men who have limited life-expectancy due to their advanced age or to serious health issues.
For more information:
– Chou R, Croswell JM, Dana T, Bougatsos C, Blazina I, Fu R, et al. Screening for Prostate Cancer: A Review of the Evidence for the U.S. Preventive Services Task Force.First published October 7, 2011 on annals.org
– [video] Screening Guidelines for Prostate Cancer Called into Question.
