The significance of changes in serum prostate specific antigen levels after a transurethral resection of the prostate

Purpose: The serum prostate specific antigen (PSA) level is known to be related with the total prostate and cancer volumes. After a transurethral resection of the prostate (TURP) in patients with benign prostatic hyperplasia (BPH), a decrease in the serum PSA level is expected. We investigated the relationship between the resected prostate specimen weight and serum PSA level. Materials and methods: Between July 1998 and March 2003, 372 patients underwent a TURP for the treatment BPH. We performed studies, including digital rectal examination, urinary flow rate, international prostate symptom score, serum PSA levels, and transrectal ultrasound (TRUS) pre-and post-operatively. We compared the resected specimen weight of the prostate with the changes in the serum PSA level using correlation and regression tests as statistical methods. Results: Removal of 1gm of BPH tissue decreased the serum PSA the average level by 0.45±0.25ng/ml. In patients with BPH, there was a strong statistical correlation and a direct proportionality between the resected specimen weight and changes in the serum PSA level (p < 0.05). Using the above mentioned statistical methods, the formula y=2.389+0.158x (x=resected specimen weight, y=changes in serum PSA levels) was derived. However, there was no statistical correlation between the two factors in prostate cancer patients. Conclusions: An elevated serum PSA level in patients with BPH is mainly caused by the enlargement of the prostate transition zone. A statistically significant difference was noted between the pre-and post-operative serum PSA levels. However, in patients with prostate cancer, the serum PSA levels showed various postoperative changes. Some patients that underwent a TURP for BPH showed no match on the previously-mentioned formula, and these patients should be carefully followed up, with serum PSA level check-ups and/or a prostate biopsy considered.