Prostate-specific antigen values and their clinical significance in renal transplant recipients

BACKGROUND: In the diagnosis of prostate cancer, prostate-specific antigen (PSA) is the most clinically useful tumor marker. Its utility in renal transplant patients is unclear. We hypothesized that PSA values might be affected by the renal function, immunosuppression, or proteinuria. METHODS: Three hundred four PSA values were measured in 166 patients >40 years (53.5 +/- 7.2 years, mean +/- SD, range 44.4 to 76.2). Charts were reviewed for 24-hour creatinine clearance, 24-hour urinary protein, cyclosporine use, age at the time of each PSA test, and evaluation done in response to the PSA result. Analyses used the Mann-Whitney U test and simple regression model. RESULTS: Twenty-five values in 13 patients were >4.0 ng/mL. Of these, 6 patients (6 values) had normal repeat PSA values; 3 patients (11 values) had negative evaluations for prostate cancer; and 4 patients (8 values) were diagnosed with prostate cancer. The latter 4 patients were excluded from the denoted normal group leaving 294 PSA values in 162 patients. The mean normal PSA was 1.3 +/- 1.8 ng/mL, range 0.1 to 20.2. The pretreatment mean PSA for recipients with prostate cancer was 302 +/- 800, range 8.0 to 2,281. An elevated PSA value was associated with a 31% incidence of prostate cancer. There was no association of PSA levels with cyclosporine use, 24-hour creatinine clearance, or 24-hour urinary protein, but there was with age. CONCLUSIONS: Prostate-specific antigen values in renal transplant recipients are similar to those in the general population and are not influenced by cyclosporine or by renal function. We recommend routine measurement of PSA in male transplant recipients.