RESUMO
The determination of prostate-specific antigen (PSA) is a useful tool in the diagnosis and follow-up of prostate cancer in males, but its diagnostic validity is uncertain in hemodialysis patients. We prospectively evaluated PSA in male hemodialysis patients as well as the influence of a single dialytic session on its levels. We measured pre- and postdialysis total PSA (tPSA) in 63 hemodialysis patients (mean age 68.44 +/- 11.16 years, range 33-86 years) who had received dialysis with low flux membranes as well as in 729 normal subjects (mean age 63.22 +/- 16.85 years, range 28-92 years). We also measured pre- and postdialysis hematocrit (Hct) in patients in order to estimate the degree of hemoconcentration after the dialysis session. If any of the examined patients or subjects had abnormal tPSA levels then free PSA (fPSA) and the f/tPSA ratio were additionally measured. Patients had lower levels of tPSA compared with those of the subjects (2.41 +/- 4.06 vs. 3.76 +/- 7.16 ng/ml, p < 0.05) while both of the two groups had near equal prevalence of individuals with abnormal values of tPSA or f/tPSA ratio (patients 12.69 and 7.93%, subjects 11.01 and 7.11%, respectively; nonsignificant. Dialysis resulted in a 9.48% increase in mean tPSA levels (2.41 +/- 4.06 vs. 2.69 +/- 4.06 ng/ml, nonsignificant) and in a 10.09% increase in mean Hct; the correlation between these increases was significant (r = 0.79, p < 0.001). In conclusion, our male hemodialysis patients had lower PSA levels compared with the general population, while both groups of individuals had a similar prevalence of abnormal values of tPSA and f/tPSA ratio. Dialysis with low flux membranes does not eliminate PSA and its postdialysis increase is due to hemoconcentration.