Influence of investigative and operative procedures on serum prostate-specific antigen concentration

We determined the effect of cystoscopy (flexible and rigid), transrectal ul trasonography (with and without needle biopsy of the prostate) and transure thral resection of the prostate or bladder tumour on the serum prostate-spe cific antigen (PSA) concentration. Samples were taken from 60 men before an d up to 14 days following these procedures. Flexible cystoscopy did not result in a significant increase in serum PSG c oncentration, with a median increase of 0.1 mu g/L (P > 0.05). Small but st atistically significant increases in serum PSA levels 1 day post-procedure were observed following rigid cystoscopy and transrectal ultrasound without biopsy. The median increase in serum PSA concentration following rigid cys toscopy was 0.15 mu g/L (P = 0.04) and following transrectal ultrasound was 0.3 mu g/L (P = 0.01). In both cases the serum PSA level had normalized by 2 days post-procedure. Transurethral resection of bladder tumours resulted in a variable rise in serum PSA, with a median increase of 2.6 mu g/L afte r 1 day, which returned to normal over 7-14 days. Ultrasound-guided needle biopsy of the prostate and transurethral resection of the prostate produced significant increases in serum PSA levels, which took up to fourteen days to return to normal. The median increase in serum PSA following needle biop sy was 6.0 mu g/L and following transurethral resection of the prostate (TU RP) was 13 mu g/L. Samples for PSA measurement may safely be taken within 24-48 h of flexible cystoscopy and transrectal ultrasonography (TRUS) providing prostatic biops y is not carried out. For other procedures it is necessary to wait for at l east 14 days to ensure that false positive PSA results are not obtained.