The National Comprehensive Cancer Network and the American Urological Association currently recommend that men who have a spike in prostate specific antigen (PSA) levels get a biopsy to test for prostate cancer — even if their overall PSA level is low and there are no other indications of cancer.
But a new study by researchers at the Memorial Sloan-Kettering Cancer Center in New York City finds that a rapid rise in PSA — or “PSA velocity” — doesn’t necessarily mean prostate cancer. In fact, for some 80% of men who were otherwise healthy and had an overall low PSA, the study found that a PSA spike — even if it doubled a man’s level — did not predict prostate cancer. And adding PSA velocity to other standard indicators of prostate cancer or to PSA scores alone didn’t do anything to increase accurate prediction of risk. (More on Time.com: How Early Balding Is Linked to Prostate Cancer)
The experiment was actually the byproduct of a drug trial: about 5,500 men over the age of 55 participated in the control arm of a trial of the drug finasteride, which is used to treat prostate enlargement. The researchers followed this placebo group through seven yearly PSA tests and an eventual biopsy (or cancer diagnosis). Once the researchers adjusted for other standard risk indicators, such as age and a physical exam, they found no reliable connection between PSA velocity and biopsy outcome.
The Wall Street Journal reported:
So rather than looking at PSA velocity, physicians should rely on the collection of indicators already used to decide if a man needs a biopsy, including his PSA level, age, digital rectal exam and family history, [study author Andrew] Vickers tells the Health Blog. Adding PSA velocity to the mix increases the number of men who receive unnecessary biopsies without catching more cases of aggressive prostate cancer.
“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,” Dr. Peter Scardino, chair of the department of surgery at Memorial Sloan-Kettering, told the BBC. (More on Time.com: Could Pomegranates Help Stop Cancer Cells?)
A surge in PSA could indicate other conditions that may require medical attention, such as a urinary infection or a benign prostate condition. And a normal PSA result does not guarantee that a man is cancer-free.
For more on prostate cancer, see the National Cancer Institute’s site.