A total of 468 men had adequate PSA history (at least 5 PSA tests over at least 4 years and no more than 2 years in between). 137 men were diagnosed with CaP, treated with radical prostatectomy (RP), and had pathology Gleason scores recorded. These RP patients were divided into high and low Gleason score groups. There were 25 men with high Gleason (defined as 4+3 or 8–10). Three hundred thirty-one men were not diagnosed with cancer. The annual growth rate in cancer PSA (PSAgr) was estimated using a consistent exponential trend plus a no-cancer baseline. Cancer PSA was estimated as the difference between the trend and the baseline. Consistent trends were fit using the full history and also excluding the last two years to test predictive power. The data was divided into high and low PSAgr groups. Each of those groups was divided into high and low cancer PSA groups. The probability of high Gleason cancer was calculated for each group.
The probability of high Gleason cancer was greater for high PSAgr trends than for low PSAgr trends (one sided p value of 0.0038 using the full history and 0.0015 for the two year prediction). The probability increased to a greater extent with increasing cancer PSA for high PSAgr than for low PSAgr. At a cancer PSA level of 3.0 the two-year prediction of risk was 2.0 times the full history. Thus, for the same cancer PSA, the risk of high Gleason cancer is greater for high PSAgr than for low PSAgr. This result suggests that the PSA threshold should be decreased for high PSAgr trends and increased for low PSAgr trends (for 6% risk for example, for all trends the cancer PSA threshold should be 3.0 but for high PSAgr the threshold should be only 0.7 PSA and for low PSAgr it should be 7.2 PSA). They pointed out that if 6% risk justifies a 3.0 cancer PSA threshold without considering PSAgr, then for high PSAgr the predicted risk justifies a 0.7 cancer PSA threshold. This is equivalent to a PSA threshold of 1.7 for a typical man with a no-cancer baseline PSA of 1.0 (1.7 compared to a 4.0 threshold).
Presented by Jasmin Bektic, MD, et al. at the 26th Annual European Association of Urology (EAU) Congress - March 18 - 21, 2011 - Austria Centre Vienna, Vienna, Austria
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