PSA velocity may help identify insignificant prostate cancer

NEW YORK (Reuters Health) - Prostate-specific antigen velocity (PSAV), increasingly recognized as a marker of potentially lethal prostate cancer, can also predict the likelihood that a given patient's cancer is insignificant, researchers say.

"A controversy of current prostate specific antigen based prostate cancer screening is the over detection of potentially insignificant prostate cancer," Dr. William J. Catalona, of Northwestern Feinberg School of Medicine, Chicago, and colleagues write. "A promising marker is prostate specific antigen velocity (rapidly increasing PSA)."

The 2010 National Comprehensive Cancer Network Guidelines recommend a PSAV threshold of about 0.35 to 0.4 ng/mL per year for prostate cancer screening protocols. Dr. Catalona and his co-authors sought to determine "whether this PSAV threshold is associated with...histologically insignificant prostate cancer at radical prostatectomy."

As they report in the January issue of the Journal of Urology, their study focused on 1073 men who underwent radical prostatectomy between 1992 and 2008. Insignificant prostate cancer was defined (on the basis of the Ohori criteria) as confined to the prostate, with a tumor volume 0.5 cc or less and no Gleason pattern 4 or 5.

The patients' mean age was 62 years. Their median PSA at diagnosis was 4.3 ng/mL, and most had a clinical stage T1c disease with a Gleason score of 6.

Preoperative PSAV greater than 0.4 ng/mL per year was significantly associated with positive surgical margins (19% versus 12%, p = 0.003) seminal vesicle invasion (4% versus 1%, p = 0.007), a Gleason score of 7 or greater (p = 0.008), and greater tumor volume.

Sixty-nine men (6%) had pathologically insignificant cancer. Insignificant disease was significantly more likely in men with preoperative PSAV less than 0.4 ng/mL per year (10%, vs. 5% for PSAV greater than 0.4 ng/mL per year; p = 0.003).

"These results suggest that PSAV may be useful in conjunction with other variables to help enhance the specificity of prostate cancer screening to detect clinically significant prostate cancer," the authors conclude.

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