This new advice comes in an update to recommendations from the USPSTF, reported in the August 5 issue of the Annals of Internal Medicine. It marks a significant change from the previous statement from the USPSTF, issued in 2002, which concluded there was insufficient evidence to recommend for or against routine screening with prostate specific antigen (PSA), but did not stipulate any age. Now it recommends no screening for men who are 75 years or older and reiterates that the benefits of screening men younger than this remain unproven.
For men who are 75 years or younger, the "evidence is inadequate to determine whether screening improves health outcomes," the USPSTF states. "Therefore the balance of harms and benefits cannot be determined."
The advice to clinicians is to discuss the potential benefits and known harms of PSA screening with male patients who are younger than 75 years. "Men in this age group should be informed of the gaps in the evidence, and their personal preferences should guide the decision of whether or not to order the test," write the authors, headed by Kenneth Lin, MD, from the Agency for Healthcare Research and Quality in Rockville, Maryland.
This advice is in line with that of most major medical organizations in the United States, the authors comment. Most other organizations also recommend that clinicians discuss the potential benefits and known harms of PSA screening with their patients, that they consider patients preferences, and that they individualize screening decisions.
Age Stipulation Is New and Surprising
However, the age stipulation is new and surprising, says David Penson, MD, associate professor of urology and preventive medicine at the Keck School of Medicine, University of Southern California. "Most other groups recommend that the individual provider should determine the patient's life expectancy and, on the basis of this, screen (or discuss screening) if the life expectancy is more than 10 years," he explained to Medscape Oncology.
"The USPSTF is the first group to tie the threshold to stop screening to a numerical age," Dr. Penson pointed out. This did surprise him, he said, adding: "It almost strikes me as ageism. After all, there are a fair number of patients over age 75 who live more than 10 years. And conversely, patients who are under age 75 who don't have a 10-year life expectancy."
"The use of an age threshold strikes me as arbitary, and doesn't take into account for individual variations or patient preferences," Dr. Penson said.
A similar reaction came from the American Cancer Society, from their director of prostate and colorectal cancer, Durado Brooks, MD, MPH. "It is surprising," he said in an interview. Establishing a fixed age at which to stop screening introduces a "new element," although one could argue that this is not strikingly different from recommending screening only for men who have a life expectancy of 10 years or more. However, this new age stipulation does not take into account the significant number of very active men who are 75 years or older, who may have a life expectancy of more than 10 years.
There is evidence in the United States that there is a significant amount of screening in men in their upper 70s and even into their 80s, Dr. Brooks commented. One recent study, which looked at PSA screening in 7 Veterans Health Administration hospitals, found this test was performed in 15% of men older than 75 years of age (Ann Int Med. 2007;167:1367-1372). "This study cannot be viewed as representative of screening practices across the United States, as the analyzed data is from Veterans hospitals and clinics in one region of the US," Dr. Brooks commented. "It does, however, give us an idea of the kinds of screening practices that are occurring in some settings."
Lead author Dr. Lin, medical officer with the USPSTF confirmed to Medscape Oncology that this is the first time that any major guideline group has made a recommendation with an explicit age cutoff value for prostate cancer screening. "Most organizations advise discontinuing prostate cancer screening in men with a life expectancy of fewer than 10 years, but this recommendation has largely gone unheeded in practice as it is extremely difficult for clinicians to predict life expectancy with any degree of precision," Dr. Lin said.
PSA screening is common in the elderly population, Dr. Lin commented. In the United States, up to one third of all men aged 75 years and older are currently receiving PSA testing, as reported in recent national surveys. There was also a study published in the Journal of the American Medical Association in 2006 that showed that even higher percentages of elderly men were receiving PSA testing within the Veterans Administration system.
Dr. Penson agrees that PSA screening is being carried out regularly in older men. "I think that most clinicians are smart enough to have detailed discussions with patients and are able to assess the patients comorbid conditions in a such a way that they can intelligently apply this test to men over 75 years of age, and often do."
Will the new advice curb this practice? "Possibly," says Dr. Brooks, as clinicians say that they consider recommendations from the USPSTF as being important. However, in practice, clinicians are often guided by their own experience with patients as much as they are by clinical guidelines, so this recommendation may influence but will not eliminate PSA screening in the older age group, he predicted.
The USPSTF also suggests that 4-year screening intervals may be as beneficial as annual screening, although the evidence base for this statement is unclear. At present, the American Cancer Society and the American Urological Association recommend annual PSA screening as well as digital rectal examinations for men older than 50 years. "I have seen some suggestions in the literature that 2-year screening intervals may be as good as annual intervals, but have not come across this 4-year interval suggestion before," Dr. Brooks commented.
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