Most older men with prostate cancer found by prostate-specific antigen (PSA) tests and biopsies opted for treatment in a new study - even if signs pointed to their disease being slow-growing and not immediately life-threatening.
Still, among men with high PSA levels, only about one-third ended up getting a biopsy to determine if they had cancer at all, researchers found.
They said those findings point to the difficult decisions, anxiety and side effects that can come after a seemingly simple choice to undergo prostate cancer screening.
"A lot of times older men just think, ‘It's a blood test, how bad can it be?'" said Dr. Louise Walter, a geriatrician from the San Francisco VA Medical Center.
"It's not just a simple blood test and then you're done and you know if you have cancer or not and you know what to do. It's one test in a cascade of tests that can lead to increasingly intensive interventions," Walter, who led the new study, told Reuters Health.
The value of screening older men for prostate cancer has been in question for years. Last year, the U.S. Preventive Services Task Force (USPSTF), a government-backed panel, recommended against PSA tests in all men, regardless of age.
Data have been conflicting about whether screening saves any lives. It's clearer that treatment after a positive test and biopsy can cause side effects such as impotence and incontinence, and that some cancers picked up on screening would never have caused symptoms because they are so slow-growing.
For their new study, Walter and her colleagues analyzed insurance claims and medical records for almost 300,000 men, age 65 and older, who were screened for prostate cancer through the VA in 2003. Of those, just over 25,000 had a PSA level above the typical cutoff of 4 nanograms per milliliter of blood.
The typical next step after a high PSA test is a biopsy, to show more clearly if a man has cancer and how serious it is. But over the next five years, just one-third of men with high PSA levels underwent biopsies, the study team reported in JAMA Internal Medicine.
"The only way PSA is going to benefit anyone is, if it's high, you follow it up with a biopsy to see, do you have an aggressive cancer as well?" Walter said. Otherwise, men just live with the worry of having high PSA levels - which they wouldn't know about if they had never been screened.
"We should talk with our patients before we send a PSA test to see if they would even remotely consider a prostate biopsy," she said. "You should definitely not be screening men who say, ‘I would not want to get a prostate biopsy.'"
Of the one-third of men who did have their high PSA levels followed up on, about 63 percent were diagnosed with prostate cancer. More than 80 percent of those men chose to be treated - typically with prostate-removing surgery or radiation.
That trend held even among men who were at least 85 years old, had multiple other health problems and had cancers with a low chance of growing and causing damage.
Side effects without benefit
In the U.S., about 239,000 men will be diagnosed with prostate cancer in 2013 but less than 30,000 will die of the disease, according to the American Cancer Society.
Based on the new results, men should consider all of the implications of a positive PSA test before they decide to get screened, Walter said. About one in seven men who were treated for prostate cancer - including cancers that wouldn't have caused any symptoms - developed incontinence or impotence as a result, her team found.
Dr. Timothy Wilt, who has studied prostate cancer screening at the Minneapolis VA Health Care System and the University of Minnesota School of Medicine, said the findings support the USPSTF's recent call against PSA testing.
"What this study shows is that there are serious, frequent and often persistent harms associated with the PSA blood test and that it's not simply a blood test but that there are downstream consequences," he said.
Along with complications from treatment, the study shows about one in 1,000 men who had a biopsy died as a result, he said - cancelling out any possible small benefit from screening on cancer-related deaths.
In another research letter published alongside Walter's study, researchers found more men would choose to get a prostate biopsy after an inconclusive PSA test - which provides no information about cancer - than after not getting tested at all.
"These results suggest that the ubiquitous use of simple but unreliable screening tests may lead to consequences beyond the initial cost and patient anxiety of inconclusive results; they may also lead to investigation momentum," wrote Dr. Sunita Sah from Georgetown University in Washington, DC, and colleagues.
"The most serious harm from testing is being diagnosed with prostate cancer and nearly all those men undergo treatment, yet treatment offers little to no reduction in prostate cancer mortality in the vast majority of those men," Wilt, who was not involved in the new research, told Reuters Health.
"Making a wise decision about PSA testing can often be to say no to the PSA test," he advised. "Men should not be tested unless they have the information about the harms and the potential small benefit and make an informed decision."