Effective Intervals of Serum Prostate Specific Antigen (PSA) Test for Screening of Prostate Cancer in Men with Initial Serum PSA Level below 2ng/ml

Ko, Young Hwii; Nam, Sang Gan; Choi, Hoon; Yoon, Jong Hyun; Yoon, Cheol Young; Cho, Jae Heung; Yoon, Duck Ki

Abstract

PURPOSE: The aim of this study was to estimate the effective intervals of the serum prostate specific antigen (PSA) test in men aged over 50 years, with an initial PSA value below 2ng/ml, no palpable nodule at digital rectal examination (DRE) and no abnormal findings on transrectal ultrasonography (TRUS).
MATERIALS AND METHODS
209 men, with initial serum PSA levels below 4ng/ml, who had checked their PSA more than twice, with a minimal interval of 4 months, taking no BPH medication and with no lesion suspicious of malignancy on DRE and TRUS, were enrolled. The factors influencing the changes in the PSA were analyzed, and the rate of conversion of PSA over the cut-off level of 4ng/ml, or age specific reference level of PSA, calculated. Another group of 24 patients, with initial PSA levels below 4ng/ml, but showing no lesion suspicious of malignancy on DRE or TRUS, underwent transrectal biopsies, and their PSA velocities (PSAV) calculated.
RESULTS
Of the 209 patients, a PSA conversion, over the age specific reference level of PSA, was not observed over a 4 years period in the group with an initial PSA below 1ng/ml. In the group with initial PSA levels between 1 and 2ng/ml, a PSA conversion of over 4ng/ml was observed in only 3.4% of patients over a 2 year period. Among 24 biopsies, 5 prostate cancers and one high grade PIN were detected, with the calculated PSAV from these patients being 0.75ng/ml/year. When this PSAV was applied as a cut-off value, the sensitivity and specificity were 33.3 and 11.1%, respectively.
CONCLUSIONS
The PSAV did not effectively predict the presence of prostate cancer in men with an initial PSA below 4ng/ml. Therefore, in men over 50, and without a lesion suspicious of malignancy on DRE and TRUS, the suggested effective intervals for screening of prostate cancer, for men with an initial PSA below 1ng/ml and between 1 and 2ng/ml, should be 4 and 2 years, respectively.