Key messages from scientific research that's ready to be acted on
Got It, Hide thisFenton JJ, Weyrich MS, Durbin S, et al. Prostate-Specific Antigen-Based Screening for Prostate Cancer: Evidence Report and Systematic Review for the US Preventive Services Task Force. JAMA. 2018;319:1914-31.
What are the benefits and harms of screening men for prostate cancer using the prostate-specific antigen (PSA) test?
Prostate cancer is one of the most commonly diagnosed cancers in men. Many prostate cancers are slow-growing and are not life-threatening. The PSA test is a blood test used to screen for prostate cancer. It can help detect prostate cancer at an early stage when it may be easier to treat. However, men with a positive PSA test may have a prostate condition other than cancer (false-positive test) or prostate cancer that is unlikely to progress and doesn’t need to be treated (overdiagnosis). Men with positive screening tests often have further, more invasive tests, such as prostate biopsy. These tests can have complications.
Researchers in the USA did a systematic review of studies available up to February 2018. They found 8 studies assessing PSA screening, including 3 randomized controlled trials (RCTs) with 647,906 men who were between 50 and 74 years of age.
The key features of the RCTs were:
Compared with no screening, PSA screening:
No prostate cancer was found in 10% to 18% of men who had a positive PSA test. In men who had a biopsy after a positive PSA test, 61% to 76% did not have prostate cancer.
Why do the 3 trials show different results for reducing death due to prostate cancer?
Differences within the trials may have affected the results. For example, some trials did PSA tests every year and some every 2 to 4 years. Trials also used different levels of PSA to indicate the need for a biopsy. If a lower PSA cutpoint was used, the PSA test would be positive for more people than if a higher PSA cutpoint was used. Some of the trials had problems: Some men in the no-screening groups had a PSA test done when they shouldn’t have (contamination), and some men who were supposed to have a PSA test done did not (poor adherence).
In men without symptoms of prostate cancer, PSA screening may or may not reduce prostate cancer mortality. Harms of PSA screening include false-positive test results, unnecessary biopsies, and overdiagnosis.
Outcomes | Number of trials (number of men) | Effects of screening |
Death due to any cause | 3 trials (647,751 men) | No benefit at 10 to 15 years of follow-up. |
Death due to prostate cancer | 1 trial (162,243 men) | 0.5% of men screened and 0.6% of men not screened died of prostate cancer over 13 years. This means about 12 fewer men out of 10,000 died of prostate cancer over 13 years because they had a PSA test done. |
| 2 trials (485,508 men) | No benefit at 10 to 15 years of follow-up. |
False-positive PSA test result | 2 trials (94,180 men) | 10% to 18% of men who were screened had a positive PSA test result, but no prostate cancer was found. |
| 3 trials (647,906 men) | 61% to 76% of men who had a biopsy after a positive PSA test did not have prostate cancer. |
Overdiagnosis | 2 trials (238,926 men) | 21% to 50% of prostate cancers that were detected by PSA screening were not important to find because they were unlikely to cause symptoms or death. |