Despite recent claims by some urologists that measuring the blood protein prostate-specific antigen (PSA) may not be effective in predicting risk of prostate cancer, a Johns Hopkins study of more than 2,000 men confirms that PSA remains the best measure of the likelihood of cancer recurrence after surgery.
Results of the study, published in the October issue of The Journal of Urology, demonstrated that men with high PSA levels prior to prostate removal surgery were significantly more likely to have advanced clinical stages of cancer, evidence of higher grade cancers in surgically removed tissue, and spread of cancer cells beyond the prostate. In addition, increasing PSA was significantly associated with increased risk of cancer recurrence after surgery, even in men with lower PSA levels prior to surgery.
The study was led by Stephen J. Freedland, M.D., clinical instructor of urology, and Alan W. Partin, M.D., Ph.D., professor and chair of urology at Johns Hopkins' Brady Urological Institute.
"In our study, PSA levels measured before prostate removal surgery were significantly associated with the risk of recurrent cancer after surgery," Freedland says. "These data support the notion that PSA remains the best available prostate cancer tumor marker. It certainly suggests that the PSA era is alive and well."
PSA is a protein produced by cells of the prostate gland. Prostate cancer can increase PSA, so the higher the PSA level, the greater the likelihood that a patient has prostate cancer. Also, higher PSA values generally reflect larger, more aggressive cancers. Freedland acknowledges that because PSA provides physicians with a measure of a patient's prostate health at a single point in time, it's "far from perfect." However, he says, "it's better than anything else we have."
"As a screening tool, PSA has done what we wanted it to do," Freedland says. "It detects advanced disease early and reduces the likelihood of metastatic disease."