How is prostate cancer diagnosed?

Currently, digital rectal examination (DRE) and prostate specific antigen (PSA) are used for prostate cancer detection. The American Urological Association recommends that healthy men over the age of 40 should consider obtaining a baseline prostate cancer screening with a DRE and PSA test. Evidence from research studies suggest that combining both tests improves the overall rate of prostate cancer detection. For more information on the DRE exam, please see the page four of our Prostate Health Playbook.
DRE: The DRE is performed with the man either bending over, lying on his side or with his knees drawn up to his chest on the examining table. The physician inserts a gloved finger into the rectum and examines the prostate gland, noting any abnormalities in size, contour or consistency. DRE is inexpensive, easy to perform and allows the physician to note other abnormalities such as blood in the stool or rectal masses, which may allow for the early detection of rectal or colon cancer.  Because the DRE by itself is not an effective way to detect early cancer, it should always be combined with a PSA test.
Prostate Specific Antigen Test (PSA): The PSA test is usually performed in addition to DRE and increases the likelihood of prostate cancer detection. The test measures the level of PSA, a substance produced only by the prostate, in the bloodstream.
The blood test can be done in a clinical laboratory, hospital or physician's office and requires no special preparation on the part of the patient. Ideally, the test should be taken before a DRE is performed or any catheterization or instrumentation of the urinary tract. Furthermore, because ejaculation can transiently elevate the PSA level for 24 to 48 hours, the patient should abstain from sexual activity for two days prior to having a PSA test.
Very little PSA is detected from patients with a healthy prostate, but certain prostatic conditions can cause larger amounts of PSA to leak into the blood. One possible cause of a high PSA level is benign (non-cancerous) enlargement of the prostate, otherwise known as BPH. Inflammation of the prostate, called prostatitis is another common cause of PSA elevation, as is recent ejaculation. Prostate cancer is the most serious possible cause of an elevated PSA level. The frequency of PSA testing remains a matter of some debate.
The American Urological Association (AUA) believes that the decision to screen is one that a man should make with his doctor following a careful discussion of the benefits and risks of screening.  In men who wish to be screened, the AUA recommends getting a baseline PSA, along with a physical exam of the prostate known as a digital rectal exam (DRE) at age 40. A disadvantage of infrequent testing is that it limits the ability to detect a rapidly rising PSA levels that can signal aggressive prostate cancer, though this is relatively uncommon for men with such low PSA values. Recently, several refinements have been made in the PSA blood test in attempts to determine more accurately, who has prostate cancer and who has false-positive PSA elevations caused by other conditions like BPH. These refinements include PSA density, PSA velocity, PSA age-specific reference ranges and use of free-to-total PSA ratios. Such refinements may increase the ability to detect cancer and these should be discussed with your physician.
It is important to realize that in most cases an abnormality in either test is not due to cancer but to benign conditions, the most common being BPH or prostatitis.