Prostate cancer test to be repeated

Men who undergo prostate specific antigen (PSA) testing for prostate cancer should undergo a second test to confirm the results if the first is positive, according to new findings. The test results can vary, and an elevated result on the first test - a sign of prostate cancer, may be lower on a second test. PSA is a protein produced by the prostate gland. PSA levels above 4 nanograms per millilitre (ng/mL) of blood can signal prostate cancer, but not always, sometimes a rise in PSA is due to another cause, and sometimes cancer can occur without a rise in PSA. About 20 percent of aggressive prostate tumours are found in men with normal PSA levels. Men with PSA levels that require further testing such as a biopsy for the presence of cancer should undergo another PSA test between four and six weeks after their initial test. This would save men from having unnecessary biopsies. Researchers at the Memorial Sloan-Kettering Cancer Centre in New York, tested blood samples from 972 men ages 35 to 89 who had originally enrolled in a study on preventing colon polyps. A total of five consecutive blood samples collected during a four-year period were tested for each man. Roughly 20 percent of the group had a PSA level that would have called for a biopsy, depending on the criteria used to trigger a test. About 50 percent of this group later had their PSA drop to levels that would not have called for a biopsy.

The study suggests that roughly 40 to 50 percent of men with an elevated PSA level may have a lower result the next time they are tested. This means some men may undergo an unnecessary biopsy, a test in which a needle is inserted into the prostate to collect cells for further testing. It was found was that PSA levels tend to fluctuate over time. About 75 percent of men who have a prostate biopsy after an elevated PSA test are found to be cancer-free.As prostate cancer often progresses slowly, the disease can sometimes go without immediate treatment. In some cases particularly when a man is elderly or in poor overall health it may not be worth asking the patient to risk the side effects of surgery, radiation or other therapy. Men should discuss the pros and cons of the test with their doctors. While PSA testing does lead to the early detection of prostate cancer, a single abnormal PSA level should be viewed with caution. A newly elevated level should be confirmed before expensive or invasive tests, such as a prostate biopsy.