High PSA velocity no predictor of prostate cancer risk
Researchers from Memorial Sloan Kettering Cancer Center say a sudden rise in PSA (prostate specific antigen) level, known as PSA velocity, is not a predictor of prostate cancer, as long as the total PSA remains low and clinical exam is otherwise normal.
The scientists studied 5000 men, finding strong evidence that using PSA velocity can lead to unnecessary biopsies. The researchers say men should be cautious about consenting to a prostate biopsy when digital exam is normal but there are variations in the test.
According to Peter T. Scardino, MD, Chair of the Department of Surgery, "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."
Guidelines from the the National Cancer Center Network and the American Urological Association recommend that men with a rapid rise in PSA or high PSA velocity undergo biopsy even if baseline PSA is normal and there are no changes in the prostate gland with a digital rectal exam.
In the study, men with PSA of 3.0 ng/mL were either given a drug to shrink the prostate gland known as finasteride or a placebo. The researchers focused on the group given placebo. The men were followed for 7 years with yearly PSA testing. Those with a PSA level greater than 4.0 ng/mL were recommended to undergo biopsy.
The study included men from the Prostate Cancer Prevention Trial who were 55 years of age or older and had no history of prostate cancer, normal digital rectal exam and PSA 3.0 ng/mL or less.
At the end of the seven years, men without prostate cancer diagnosis were asked to consent to biopsy. The researchers found there was no association between results of the PSA velocity and outcomes of biopsy. The researchers found PSA testing is a better indicator for prostate cancer than PSA velocity.
JNCI J Natl Cancer Inst (2011)103 (6): 462-469.doi: 10.1093/jnci/djr028
“An Empirical Evaluation of Guidelines on Prostate-specific Antigen Velocity in Prostate Cancer Detection”
Image credit: Wikipedia commons
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