A new study on the use of prostate-specific antigen (PSA)-based prostate cancer screening in the United States found that many elderly men may be undergoing unnecessary prostate cancer screenings. Using data from surveys conducted in 2000 and 2005, researchers report that nearly half of men in their seventies underwent PSA screening in the past year - almost double the screening rate of men in their early fifties, who are more likely to benefit from early prostate cancer diagnosis and treatment. Further, men aged 85 and older were screened just as often as men in their early fifties.
Because prostate cancer tends to be slow-growing, data show that many men - particularly those in their seventies and older - will die of other causes before prostate cancer becomes a problem that requires medical attention. The new findings underscore a long-standing concern that overuse of PSA screening and PSA-based treatment decisions may lead to unnecessary treatment of many older men and potential complications such as incontinence, impotence and bowel dysfunction.
"Our findings show a high rate of elderly and sometimes ill men being inappropriately screened for prostate cancer. We're concerned these screenings may prompt cancer treatment among elderly men who ultimately have a very low likelihood of benefitting the patient and paradoxically can cause more harm than good," said senior author Scott Eggener, MD, assistant professor of surgery at the University of Chicago. "We were also surprised to find that nearly three-quarters of men in their fifties were not screened within the past year. These results emphasize the need for greater physician interaction and conversations about the merits and limitations of prostate cancer screening for men of all ages."
While large declines in prostate cancer metastases and death rates in the last 20 years coincide with widespread use of PSA-based screening, questions remain about its use. Data have been unclear about when men should be considered for PSA screening and when screening should stop, and recent studies have provided conflicting evidence on whether routine PSA screening in the general population of men actually reduces the risk of dying from prostate cancer. Based on these concerns, major organizations such as the American Cancer Society now encourage men who expect to live at least 10 years to talk with their doctor about the risks and benefits of screening, starting at age 50 for men with an average risk or at age 45 for men with a higher risk.
In this study, the researchers examined results from health surveys of randomly selected households conducted in 2000 and 2005 as part of the federal government-sponsored National Health Interview Survey. In addition to reviewing survey data, which included information on age, smoking, mass-body index, underlying medical conditions and other factors, the investigators calculated the estimated five-year life expectancy of each man over 40 who had received a PSA test.
They divided survey results of men age 70 and older into five-year age groups (70 to 74, 75 to 79, 80 to 84, and 85 years and older). In all, 2,623 men ages 70 and older were included in the analysis, while nearly 12,000 men between the ages of 40 and 69 served as controls.
The overall PSA screening rate within the past year for men aged 40 and older was 23.7 percent in 2000 and 26.0 percent in 2005. The PSA screening rate was lowest in the 40 to 44 age group (7.5 percent). Researchers found that the PSA screening rate was 24.0 percent in men ages 50 to 54, increasing with age until a peak of 45.5 percent in ages 70 to 74. Screening rates then declined with age, with 24.6 percent of men 85 or older reporting being screened.
Among men who were 70 or older, the investigators did find that PSA screening was more common in men with a greater estimated five-year life expectancy. For example, approximately 47.3 percent of men who were unlikely to die in five years (an estimated chance of 15 percent or less) were screened, 39.2 percent of men with an intermediate chance (16 to 48 percent probability) of dying received screening, and 30.7 percent of those with the highest probability of death (48 percent or greater) in five years were screened.
Eggener offered some possible explanations for the results, noting that screening rates may reflect how frequently men visit primary care physicians. Older men tend to have more health problems that require doctor visits, and this may in turn result in more frequent PSA testing than younger men, who see their doctors less. The authors suggest that physicians should be more selective in recommending PSA testing for older men, particularly those with a limited life expectancy, and consider more routinely screening younger, healthier men who are most likely to benefit from early prostate cancer diagnosis and related treatment. Men are encouraged to talk with their doctor about their individual risk for prostate cancer, and about the risks and benefits of prostate cancer screening.
ASCO Perspective:
Nicholas Vogelzang, MD, ASCO Cancer Communications Committee member and prostate cancer specialist
"The underuse of PSA testing in younger men, as well as the often unnecessary overtreatment of older men with indolent prostate cancer that will most likely never bother them, remain huge concerns for oncologists. This study reinforces the notion that accurately determining life expectancy, taking into consideration a variety of factors, including age and co-existing medical conditions, is often critical to deciding on appropriate screening and subsequent treatment of men with prostate cancer."
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