Screening is the use of medical testing to identify people with an increased chance of having a disease. It is done among patients without symptoms or other reasons to seek medical care. Screening patients helps doctors to determine if further testing is worthwhile. There are generally two ways that your doctor and/or urologist screen for prostate cancer: a PSA blood test and a digital rectal examination (DRE). Screening for prostate cancer may lead to early detection and treatment of prostate cancer. In most instances, early prostate cancer does not cause symptoms (i.e., difficulty urinating). Because of this, urologists rely on these two screening methods to detect prostate cancer early.
However, prostate cancer screening is not right for all men. The American Urological Association (AUA) guides urologists with regard to selecting men for prostate cancer screening, with the following recommendations:
- Men under 40 years of age are not recommended to undergo screening as clinically detectable prostate cancer is rare in this age group.
- Screening is not recommended in men between ages 40-54 who are at average risk. However, those at higher risk — including African American men and those with a family history of deadly prostate cancer spanning multiple generations or in first-degree relatives — may justify screening at this age.
- Among men 55-69 years of age, shared-decision making is recommended between physicians and patients to decide if prostate cancer screening is right for each man.
- Finally, screening is not recommended among men older than 70 years of age or in any man with less than 10-15 years of life expectancy, though some men 70+ years of age in excellent health may benefit from prostate cancer screening.
PSA (prostate-specific antigen) is a protein made by the prostate gland that is detected in the blood, with a normal value generally between 0-4 ng/mL. However, the 4 ng/mL threshold is not applied consistently. It also may need to be tailored based on specific patient characteristics.
While PSA testing is performed to assess for prostate cancer, there are other reasons for PSA levels to be elevated. These include benign prostatic enlargement (known as hyperplasia; a big prostate typically makes more PSA), and chronic inflammation or infection (i.e., prostatitis; which may or may not cause symptoms). This means that just because a PSA is elevated does not mean that a man has prostate cancer! Confusingly, a low PSA test result also doesn’t mean that a man doesn’t have prostate cancer. However, in general, men with higher PSA levels have a higher overall risk of prostate cancer.
If you have elevated PSA levels, your urologist will discuss the pros and cons for further testing. These include biomarker tests (urine or blood tests), magnetic resonance imaging (MRI), or prostate biopsy. During a prostate biopsy — which is the only way to diagnose prostate cancer — your doctor will use an ultrasound to guide the sampling of small pieces of prostate tissue. A pathologist looks at these tissue samples under a microscope to see if prostate cancer is present.
Men who undergo PSA screening typically will have a blood test every year or two during recommended screening ages (see above) to check the trend in PSA values over time. However, a man’s urologist may check his SA more often if they have concerns.
Additionally, the AUA suggests that a routine screening interval of two years or more may be preferred over annual screening among men who have participated in shared-decision making. Ultimately, intervals for screening should be individualized for each patient and based on the baseline PSA level.
Digital Rectal Examination
A DRE is the second way that some doctors screen for prostate cancer. During a DRE, the physician inserts a gloved index finger into the rectum, feeling the surface of the prostate gland for “lumps or bumps” which may be a sign of prostate cancer. This exam also gives the physician an idea regarding the size of the prostate gland.
In some instances, the PSA may be in the normal range but a DRE detects a prostate nodule (a lump or growth) which may be prostate cancer. Just like men who are suspected of having prostate cancer based on an increased PSA level, a prostate biopsy is needed to make the diagnosis.
Ultimately, the decision to undergo prostate cancer screening using PSA blood testing and digital rectal examination should be made after you and your doctor or urologist discuss the risks and benefits of this approach.