PSA elevation during prostate cryosurgery and subsequent decline

Purpose: To determine the immediate effect of prostate cryosurgery on PSA and the subsequent decline. Methods and materials: PSA level was measured in 14 patients who underwent cryosurgery for prostate cancer. Blood samples were taken immediately before and after cryosurgery and 1, 2, 4, 6 weeks and 3 months postoperatively. A confidence interval for the elevation from baseline to maximal PSA was calculated. PSA decline was assessed in patients with a nadir PSA ≤0.5 ng/mL. Patients with a postoperative nadir PSA >0.5 ng/mL were considered to harbor viable cancer and were excluded from the decline analysis. The observed PSA levels during the postoperative period were compared with the expected levels that were calculated according to the maximal PSA level and a serum half-life of 2.5 days. Student t-test was used to compare expected and observed PSA levels. Results: PSA increased from an average of 9.23 ng/mL preoperatively to a maximum average of 155 ng/mL (maximal PSA ranges: 18.9-490.5 ng/mL). The 95% CI for the increase in PSA from baseline level was 63.4 to 224.14. PSA nadir ≤0.5 ng/mL was achieved in 10 patients. The observed PSA decline course was slower than expected according to its half-life. Average observed and expected PSA levels at 2,4 and 6 weeks after cryosurgery were 10.4 versus 3.57ng/mL (P = 0.005), 0.65 versus 0.07 (P = 0.007) and 0.09 versus 0.001 (P = 0.03), respectively. Conclusion: PSA levels increase steeply following cryosurgery, and decline slower than expected according to the serum half-life.