Screening Smarter, Not Harder, for Prostate Cancer FREE

Prostate cancer is the most commonly diagnosed non–skin cancer among U.S. men. It can be life-threatening, and many men have cancer without knowing it. For those reasons, doctors sometimes look for prostate cancer in healthy men (screen for cancer) by measuring blood levels of prostate-specific antigen (PSA), a protein secreted by the prostate gland. High PSA levels can be caused by cancer and may lead a doctor to take a sample of prostate tissue to see whether cancer is present (biopsy). Most prostate cancer grows very slowly, however, and many men with prostate cancer die of other causes. Neither PSA testing nor prostate biopsy tells doctors with certainty which cases of prostate cancer are threatening and which require treatment. As a result, many men with slow-growing cancer have biopsies and treatment after PSA testing that they would not have needed if doctors had never tested. For that reason, a group of experts recently recommended against prostate cancer screening with PSA testing. They concluded that men are hurt more than they are helped by the test. Their recommendation was based on standard practice, where men are tested every year and referred for biopsy and treatment at certain PSA levels. It is possible that using the PSA test differently (for example, by testing less often) would still be useful but reduce the harms of unnecessary treatment that come from more frequent testing.

To see whether there are ways of using PSA testing to “screen smarter, not harder,” for prostate cancer and reduce the harms of current PSA testing.

This study did not involve real people. Instead, it fed information from many research studies and sources into a computer model.

The researchers used the computer model to understand how 35 ways of using the PSA test may affect patients. The model calculated the number of men whose lives would be saved and the number of PSA results that would lead to unnecessary prostate biopsy if men started or stopped screening at different ages, were screened more or less frequently, or had biopsies at different PSA levels.

Several ways of using the PSA test helped men while reducing the harms of testing. One way was stopping screening at age 70 years because men older than 70 years tend to have higher PSA levels without prostate cancer, or if they have cancer, it is slow-growing. Other ways included measuring PSA levels less frequently in men whose levels are normal when first measured and requiring that older men have higher levels before they go for biopsy and possible unnecessary treatment.

The study relied on a computer model that used real patient information but did not directly observe the results of the screening strategies. The study did not incorporate any measure of men's preferences (for example, finding cancer early or avoiding unnecessary testing or treatment).

There may be ways to “screen smarter” for prostate cancer with PSA testing, which probably require using the PSA test less often and recommending that some men with high PSA values avoid biopsy. Those changes may lead to a few missed cases of prostate cancer but would benefit far more men than they hurt by avoiding unnecessary testing and treatment that results from more intensive use of the PSA test.