Lower PSAV Threshold Useful
Velocity below 0.4 ng/mL per year accurately detects insignificant PCa.
The finding suggests that PSAV “may be a useful adjunct in prostate cancer screening to help selectively identify clinically significant disease,” researchers concluded. They reported findings here at the 2008 Genitourinary Cancers Symposium.
Recent studies suggest the use of a lower PSAV threshold in the range of 0.4 ng/mL per year, especially in men with a PSA level below 4 ng/mL, and the 2007 National Comprehensive Cancer Network Guidelines recommend a prostate biopsy for men with a PSA below 2.5 ng/mL and a PSAV greater than 0.35 ng/mL per year. However, the researchers said there has been concern that lower thresholds could lead to detection of more insignificant cancers.
In the new study, Stacy Loeb, MD, of Johns Hopkins Medical Institutions in
All had a calculable PSAV and data on pathological tumor volume. Of the 556 men, 48 (9%) and two (0.4%) met the Ohori and Epstein criteria, respectively, for insignificant cancer, the researchers reported. The Ohori criteria include organ-confined tumor, tumor volume of 0.5 cc or less, and no Gleason pattern 4 or 5. Epstein criteria include organ-confined tumor, tumor volume less than 0.2 cc, Gleason score less than 7.
Both men who fulfilled the Epstein criteria had a total PSA level below 4 ng/mL and a PSAV less than 0.4 ng/mL per year. Patients with a PSAV below 0.4 ng/mL per year were significantly more likely to meet the Ohori criteria for insignificant cancer. Men with a PSAV higher than 0.4 ng/mL per year had a significantly higher Gleason score and tumor volume.
In a separate study, Dr. Loeb, working with H. Ballentine Carter, MD, of the Brady Urological Institute in Baltimore, and other investigators participating in the Baltimore Longitudinal Study on Aging, showed that PSAV is a significant predictor of high-risk and fatal prostate cancer and that pre-treatment PSA doubling time (PSADT) does not distinguish which prostate cancer patients have life-threatening disease, the investigators found.
The study included 694 men divided into three groups: those with no cancer (583 men), those with prostate cancer (79 men), and those with high-risk prostate cancer (32 men). This latter group included men with a PSA level of 20 ng/mL or higher, a Gleason score of 8-10, or confirmed death from prostate cancer (17 men).
Men with fatal cancer had a median PSAV of 1.64 ng/mL per year whereas those with non-fatal cancer had a median PSAV of 0.46 ng/mL per year, a significant difference between groups. Men with fatal and non-fatal cancer had a median PSADT of 5.1 and 3.1 years, a nonsignificant difference between groups.