Examples of outcomes with and without PSA testing in men ages 55 to 693*
|Outcomes||Without PSA testing||With PSA testing|
|Prostate cancer deaths in men who were followed over a 13-year period||About 6 out of 1,000 men will die of prostate cancer.||About 5 out of 1,000 men will die of prostate cancer.|
|Prostate cancers found in men who were followed over a 13-year period||About 68 out of 1,000 men will be diagnosed with prostate cancer.||About 102 out of 1,000 men will be diagnosed with prostate cancer.|
|Risk of receiving treatment you don't need||None||About 27 out of 1,000 men may get treatment they don't need.|
High PSA results that are not cancer (false-positives)3, 4*
|High PSA results that are not cancer (false-positives)||Out of 1,000 PSA tests, about 170 will find a high PSA level. Out of those 170 high PSA test results, about 129 will not be from cancer, while about 41 of the 170 will be from cancer.|
These numbers are from a large study done on the value of PSA testing. The study was done in Europe and did not include people of African descent, who are at higher risk of prostate cancer.3 A smaller study done in the United States did not find that PSA testing saved lives.1
*Based on the best available evidence (evidence quality: moderate to high)
The quality of the evidence about PSA benefits is moderate.
A large study of prostate cancer screening showed that out of a group of 1,000 men ages 55 to 69 who have PSA testing and are followed over a 13-year period:3
- Prostate cancer is more likely to be found with PSA testing than without PSA testing. About 102 out of 1,000 men who are screened will be diagnosed with prostate cancer versus about 68 out of 1,000 men who are not screened.
- PSA testing may prevent a small number of deaths from prostate cancer. About 5 out of 1,000 men who are screened will die of prostate cancer versus about 6 out of 1,000 men who are not screened.
The quality of the evidence about PSA risks is high.
Many cancers found by PSA tests would not have caused a problem if they had not been found through screening. But when cancers are found, they often get treated with surgery to remove the prostate or with radiation. These cancer treatments may not have been needed. And they can have serious side effects, such as urinary, bowel, and erection problems.
Take a group of 1,000 men ages 55 to 69 who have PSA tests. About 27 of these men may get cancer treatment they don't need.3
PSA tests can show high levels of PSA that aren't caused by cancer (called a false-positive). This means you may need more tests—like a prostate biopsy—to check for prostate cancer. These tests can be harmful. For example, prostate biopsies can cause infections. For a few people, these infections are very serious. These tests can also cause a lot of worry.
Out of 1,000 PSA tests, about 170 will find a high PSA level. But most high PSA levels are not caused by cancer. Out of those 170 high PSA test results, about 129 will not be from cancer, while about 41 of the 170 will be from cancer.3, 4
Understanding the evidence
Some evidence is better than other evidence. Evidence comes from studies that look at how well treatments and tests work and how safe they are. For many reasons, some studies are more reliable than others. The better the evidence is—the higher its quality—the more we can trust it.
The information shown here is based on the best available evidence.3, 4 The evidence is rated using four quality levels: high, moderate, borderline, and inconclusive.
Another thing to understand is that the evidence can't predict what's going to happen in your case. When evidence tells us that 2 out of 100 people who have a certain test or treatment will have a certain result and that 98 out of 100 will not, there's no way to know if you will be one of the 2 or one of the 98.