Background and Purpose:Holmium laser enucleation of the prostate (HoLEP) is a well-established technique for the treatment of benign prostatic hyperplasia (BPH). To date, changes in serum prostate specific antigen (PSA) after HoLEP have not been published. We hypothesized that HoLEP produces a diminution in PSA similar to that produced by the gold-standard therapies for BPH. To test this hypothesis, we have examined PSA data before and after HoLEP from two institutions performing high volumes of this procedure.Patients and Methods:Between August 1998 and September 2004, 509 HoLEPs were performed at two institutions for which complete PSA data were available. Preoperative demographic and transrectal ultrasonography (TRUS) volume measurements were recorded; postoperative pathology and TRUS volume were obtained. Change in PSA as a function of the weight of prostate resected and the relation of preoperative TRUS volume to PSA was determined.Results:The average weight of adenoma resected was 49.8 g (range 5–300 g) in the McGill group and 90.4 g (range 7.9–312 g) in the Methodist Hospital group. The mean decrease in PSA was 81.7% in the McGill group (range 6.0–1.1 ng/mL; P< 0.0001) and 86.0% in the Methodist Hospital group (range 8.6–1.2 ng/mL; P< 0.0001). Log transformed preoperative PSA correlated well with TRUS volume (r= 0.45), as did the weight of adenoma resected with absolute change in PSA (r= 0.38). The TRUS volume decreased significantly, from 111.9 cc to 26.5 cc, in the Methodist Hospital group (P< 0.0001).Conclusion:The HoLEP procedure produces a significant diminution in PSA that correlates well with the weight of adenoma resected. Measurement of PSA may be a useful tool for the objective assessment of ablative therapies for BPH, as the reduction in PSA corresponds well with the amount of adenoma removed.