EJACULATION INCREASES THE SERUM PROSTATE-SPECIFIC ANTIGEN CONCENTRATION

Objectives. To determine the effect of ejaculation on the serum prosta te-specific antigen (PSA) concentration in men at risk for developing prostate cancer.Methods. A prospective, community-based study was cond ucted in which 64 men, aged 49 to 79 years, underwent a serum PSA dete rmination immediately before ejaculation (baseline) and at 1 hour, 6 h ours, and 24 hours following ejaculation. The serum PSA also was measu red 48 hours and 1 week after ejaculation if the concentration had not returned to the baseline Value by the previous time interval. All sub jects abstained from ejaculation for a minimum of 7 days prior to the study and until the PSA concentration returned to the baseline level. Absolute and relative change in serum PSA concentration, as well as th e time to return to baseline PSA concentration following ejaculation, were assessed. Results. The serum PSA concentration increased followin g ejaculation in 87% of the subjects. The mean baseline PSA was 1.8 ng /mL (median, 0.7 ng/mL). The mean absolute PSA change +/- standard dev iation 1 hour, 6 hours, 24 hours, and 48 hours after ejaculation was 0 .8 +/- 1.32 ng/mL, 0.3 +/- 0.66 ng/mL, 0.2 +/- 0.33 ng/mL, and 0.4 +/- 0.40 ng/mL, respectively. The mean relative PSA change +/- standard e rror 1 hour, 6 hours, 24 hours, and 48 hours after ejaculation was 41 +/- 4%, 9 +/- 1.5%, 8 +/- 1.3%, and 10 +/- 2.3%, respectively. The abs olute and relative changes in PSA concentration noted 1 hour, 6 hours, and 24 hours after ejaculation were statistically significant (P = 0. 0001). A strong correlation was observed between absolute change in PS A and baseline serum PSA, at each time interval (1 hour: r = 0.68, 6 h ours: r = 0.77, 24 hours: r = 0.70; P < 0.0001) after ejaculation. Sim ilarly, a significant correlation was noted between absolute change in PSA and patient age at each time interval (1 hour: r = 0.37, 6 hours: r = 0.38; P = 0.002, 24 hours: r = 0.55; P < 0.0001). Ninety-two perc ent of subjects returned to baseline by 24 hours (95% confidence inter val (CI) = 83% to 97%), whereas 97% of subjects returned to baseline b y 48 hours (95% CI = 89% to 99%). Conclusions. Ejaculation causes a si gnificant increase in the serum PSA concentration in men between 49 an d 79 years of age that may persist for up to 48 hours. This change app ears to correlate with age and baseline PSA. It is recommended that me n abstain from ejaculation for 48 hours prior to having a serum PSA de termination.