Screening & Diagnosis
The following tests are useful for detecting prostate cancer:
Digital Rectal Exam (DRE): Using a gloved, lubricated finger the doctor examines the prostate to check for lumps or other abnormalities. If anything suspicious is found, additional testing may be needed. While a DRE is a useful screening tool, it is important to note that in some cases cancer may be present in the prostate without abnormalities that can be felt by the physician.
PSA Test: Blood is drawn to test the amount of prostate-specific antigen (PSA), a protein made by the prostate gland and found in the blood. High PSA levels can be associated with prostate cancer. Until recently, a PSA value above four was the accepted trigger point for a prostate biopsy. However, recent studies have shown that 15 percent of cancers are diagnosed at PSA values below three, and 15 percent of those are aggressive in behavior. Having a yearly PSA test can establish a rate of increase, known as "PSA velocity." A rapid rise may indicate an underlying cancer. It is also important to note that other noncancerous conditions may also cause a high PSA level, notably benign prostatic hyperplasia (BPH) and prostatitis.
PCA 3 Test: This relatively new test for prostate cancer measures levels of the prostate cancer gene 3 (PCA3) in urine. In some cases, this test may help diagnose prostate cancer in patients who have elevated PSA levels but a negative biopsy.
The only sure way to learn whether a man has prostate cancer is to do a biopsy — a study on a small sample of prostate tissue.
If cancer is suspected, a prostate biopsy is performed to determine if it really is cancer or a less serious condition like BPH. If prostate cancer is present, the biopsy will also help determine the extent, or stage, of the cancer and the Gleason score.
The Gleason score grades how different the biopsied tissue is from healthy prostate tissue. Gleason scores range conventionally from five or six to 10, and allow physicians to categorize how aggressive the cancer is (low, intermediate or high).
A low Gleason score (typically a total Gleason score of six) means the cancer tissue closely resembles normal prostate tissue and is not as likely to spread. The higher the Gleason score, the more aggressive the cancer and the more likely it is to spread.