They added that PSA velocity is a poor predictor of prostate cancer and often leads to unneeded biopsies and the anxiety and discomfort for the patient that goes with them.
Lead author, Andrew Vickers, PhD, said, "We have found no evidence to support the recommendation that men with a high PSA velocity should be biopsied in the absence of other indications. In other words, if a man's PSA has risen rapidly in recent years, there is no cause for concern if his total PSA level is still low and his clinical exam is normal."
Prostate cancer only affects males. The cancer starts growing in the prostate - a gland that forms part of the male reproductive system. The epithelial cells in the prostate gland produce PSA, a protein that helps keep semen in its liquid state. Some of the PSA eventually gets into the bloodstream. A man's PSA level can be measured with a blood test. A high PSA reading could be an indication of some kind of prostate condition, including cancer.
According to the National Cancer Institute, 217,730 new cases of prostate cancer were diagnosed in the USA in 2010, and 32,050 men died of the disease. It is the most common male cancer in America, and the second leading cause of cancer deaths among men.
The authors explain that PSA screening is extensively used for prostate cancer detection. Over-diagnosis is becoming a problem, resulting in unnecessary anxiety and treatments.
The American Urological Association guidelines advise a surgical biopsy for those found to have a high PSA velocity (PSA levels rise rapidly), even if the doctor finds no other indicators pointing to cancer. Other indicators may include a positive digital rectal exam or high baseline PSA.
The researchers looked at data on 5,519 males from the Prostate Cancer Prevention Trial. They were all aged 55 years or more and had no previous prostate cancer diagnosis, all had normal digital rectal exams and a baseline PSA of no more than 3.0 ng/mL. They were randomly selected to finasteride, a medication used for patients with an enlarged prostate (BPH, or benign prostatic hypertrophy), or a placebo. Treatment lasted seven years.
The researchers were interested in the control group, those on the placebo. They received annual PSA screenings. Those with a PSA of over 4.0 ng/mL were advised to have a biopsy. At the end of seven years those who did not have a prostate cancer diagnosis were invited to consent to an end-of-study biopsy.
After making adjustments for age, race and PSA levels, the scientists found no significant link between rapidly rising PSA levels and biopsy outcomes. It was not the rate of rise that predicted cancer likelihood, but rather the actual PSA level itself. In other words, a man with a steady PSA level of 5 ng/mL was more likely to be found to have prostate cancer than one whose level rose from 2.5 to 3.4ng/mL.
According to Peter T. Scardino, MD, said:
"This study should change practice. We have previously published papers determining that PSA naturally varies from month to month and have urged men whose PSA suddenly rises to wait six weeks and repeat the test before agreeing to a needle biopsy. This new study in a large population of men provides even stronger evidence that using changes in PSA as a basis for recommendation for biopsy leads to many more unnecessary biopsies and does not help to find the more aggressive cancers that we want to find and treat.
Men should be cautious before rushing into a biopsy for minor variations in their PSA level."
Written by Christian Nordqvist