ORLANDO, FL USA (UroToday.com) - Dr. Behfar Edhaie, from Memorial Sloan Kettering Cancer Center, presented an abstract on whether isolated changes in PSA levels among men under active surveillance (AS) should be used as an indication for reclassification biopsy. He presented the data on 676 men with diagnosis of prostate cancer (PC) from 1995-2011 who were managed with AS. The group excluded those men who had fewer than 4 PSA results available. In this study, PSA variation was described by studying the frequency with which a patient’s PSA level reached a threshold and then went below that level. The a priori threshold for PSA was 7ng/mL as this is the midpoint between the biopsy threshold (4ng/mL) and an accepted criterion for intermediate risk disease (10ng/mL). Moreover, they repeated this analysis for the biopsy threshold of 4ng/mL. PSA variation was examined by calculating the frequency in which change in PSA across consecutive measurements, as followed by an inverse change of equal or greater magnitude, occurred. The association between each measure of variation and number of PSA measurements was assessed using linear regression.
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A total of 541 men met the inclusion criteria. In this study, the cumulative incidence of discontinuing AS for definitive treatment within 5 years was reported at 13%. Among 251 (46%) patients who reached a PSA of 7ng/mL, 186 (74%) decreased from this threshold level at least one time. Among men with a PSA of 4ng/mL (417 patients or 77%), PSA measurements fluctuated around this threshold less often. In patients who reached a PSA of 4ng/mL or 7ng/mL, the number of PSA measurements was significantly associated with the frequency of variation across each threshold (p < 0.001). 87% of the cohort experienced at least one change in PSA direction, and the frequency of these changes was significantly associated with the number of PSA measurements (p < 0.001). Moreover, 238(44%) patients experienced a clinically meaningful change in their PSA direction. Authors reported that the frequency of these changes was significantly associated with the number of PSA measurements (p < 0.001).
PSA is frequently used in active surveillance (AS) programs to direct the course of management and re-biopsy. In this abstract, considerable fluctuation in PSA levels was reported. This study has shown that the frequency of changes in PSA increases with more PSA measurements, and because of this, an isolated change in PSA level should not be used as a trigger for re-biopsy.
Presented by Behfar Ehdaie, MD, MPH at the American Urological Association (AUA) Annual Meeting- May 16 - 21, 2014 - Orlando, Florida USA
Memorial Sloan Kettering Cancer Center, New York, NY USA
Written by Reza Mehrazin, MD, medical writer for UroToday.com