CLEARANCE OF SERUM PSA AFTER OPEN SURGERY FOR BENIGN PROSTATIC HYPERTROPHY, RADICAL CYSTECTOMY, AND RADICAL PROSTATECTOMY

Objective: To study the clearance of serum prostate-specific antigen ( PSA) after several types of prostatic tissue ablation. Methods: Serum PSA levels were measured (YANG Proscheck ultrasensitive assay) just be fore surgery, immediately after specimen removal, then twice weekly fo r 5 weeks or until it was undetectable (<0.05 ng/ml) in patients under going radical cystoprostatectomy for bladder cancer (n = 10), or radic al prostatectomy for T1 T2 prostate cancer (n = 18) and daily for 6 da ys after open surgery for benign prostatic hypertrophy (BPH) (n = 10). Results: Open enucleation for BPH: the immediately postoperative PSA level was 6 times its preoperative value. It decreased following a mon oexponential curve with a very short half-life of 0.55 +/- 0.39 days, range (0.14-1.3), reaching a value lower than the preoperative level i n all cases, except one by day 3. After radical cystoprostatectomy: th e decrease of serum PSA is monoexponential with a half life of 1.92 +/ - 1.2 days (0.57-4.24) reaching undetectable level (<0.05 ng/ml) in al l patients by day 21. After radical prostatectomy: 11/18 patients (61% ) showed a one-component exponential decrease in PSA with a half-life of 2.5 +/- 1.33 days (range 0.97-4.6 days), and 7/18 showed a two-comp onent exponential decrease with a first half-life of 0.94 +/- 0.8 days and a second of 7.62 +/- 6.35 days); 100% of the patients reached und etectable serum PSA by day 28 in the first group compared to 14.2% of the patients with a two component exponential decrease (P < 0.01). The re was no difference between these groups as far as preoperative PSA l evels and specimen pathology were concerned. Conclusion: Serum clearan ce of PSA after extirpative prostatic surgery is closely related to th e type and indication of procedure used. Radical cystoprostatectomy is probably the best model in which to study the pharmacokinetics of PSA . (C) 1995 Wiley-Liss, Inc.