Background: This article summarizes the experience and results of different prostate carcinoma screening projects using total prostate-specific antigen (PSA) and percent free PSA as the initial test. Methods: The twelve projects studied included: (1) a mass screening study using PSA as the initial test in 21,079 volunteers; (2) an investigation of the usefulness of normal and age-referenced PSA cut-offs in 1,618 men; (3) a PSA-based screening study of 2,272 asymptomatic blood donors; (4) an investigation of the evidence and significance of transition zone carcinoma in 340 men with negative digital rectal examination findings; (5) determination of percent free PSA in one retrospective and two prospective studies to determine the appropriate cutpoints for percent free PSA; (6) evaluation of the diagnostic benefit of PSA transition zone density in 308 screening volunteers; (7) a study of the impact of PSA-based screening on the percentage of incidental prostate carcinoma in 1,543 men undergoing transurethral resection of the prostate; (8) an evaluation of the changes in total PSA and pathologic stages in radical prostatectomy over 5 years in a PSA-based mass screening program; (9) a study evaluating the probability of having prostate cancer given the patient’s age, total PSA and digital rectal examination findings; (10) an evaluation of the correlation between preoperative predictors and pathologic features in radical prostatectomy specimens; (11) an investigation of the correlation of total PSA with pathologic stage and tumor volume in patients undergoing radical prostatectomy with low PSA cut-off level, and (12) a study whether age has an impact on the extension of prostate cancer. Results: (1) of the 21,079 volunteers, 1,618 (8%) had elevated PSA levels. Of these men, 778 (48%) underwent biopsies; 197 biopsies were positive for prostate carcinoma and 135 underwent radical prostatectomy. Ninety-five were found to be organ-confined. (2) A PSA cut-off of 2.5 ng/ml in men aged 45–49 years and of 3.5 ng/ml in men aged 50–59 years resulted in an 8% increase in the detection rate of organ-confined disease. (3) Of the 2,272 men, 284 had elevated PSA levels and prostate carcinoma was detected in 62 men. All patients underwent radical prostatectomy and histologic examination revealed organ-confined tumor in all but 8 men. (4) Ninety-eight of 340 men had biopsies positive for carcinoma; 28 of these patients (28.5%) had carcinoma that originated in the transition zone only. (5) In the retrospective study, receiver-operating characteristic curve analysis showed that by using a percent free PSA of 18% as a biopsy criterion, 37% of the negative biopsies could be eliminated although 94% of all carcinomas would still be detected. In the first prospective study, 106 of 158 men with elevated PSA levels <10.0 ng/ml were further evaluated and 37 prostate carcinomas were detected. By using a % free PSA of <22% as a biopsy criterion, 30% of the negative biopsies could be eliminated although 98% of the carcinomas would still be detected. In the second prospective study, 120 of 465 men with total PSA levels between 1.25 and 6.49 ng/ml and a % free PSA <18% were further evaluated and 27 (22.5%) were found to have prostate carcinomas. (6) Receiver-operating characteristic curve analysis for PSA transition zone density showed that by using a PSA transition zone density of >22 ng/ml/cm<sup>3</sup> as a biopsy criterion, 24.4% of negative biopsies could be avoided without missing a single carcinoma. (7) In the prescreening era the incidence of T1a grade 1 and 2 carcinomas was 3.1% and the incidence of T1a grade 3 and T1b carcinoma was 2.3% whereas in the years after the establishment of PSA-based screening the incidence was 4.6 and 1.03% respectively. (8) The rate of organ-confined tumors increased from 28.7% in 1993 to 65.7% in 1997. (9) In this evaluation a new approach to proceed with a prostate biopsy based upon the individual risk of having prostate cancer rather than a single PSA cutpoint was developed. (10) High total PSA levels, PSA density and PSA transition zone density correlated significantly with high Gleason scores, capsular penetration, a high percentage of cancer in the prostatectomy specimen and a high cancer volume. (11) In this evaluation all of the 95 patients with PSA levels <3.99 ng/ml who underwent radical prostatectomy showed clinically significant, organ-confined prostate cancer with negative surgical margins. (12) The results of this evaluation suggest that older men have larger tumor volumes compared to younger men with the same PSA levels. Conclusions: These data suggest that PSA-based screening with low PSA cut-off values increase the detection rate of clinically significant, organ-confined and potentially curable prostate cancer. Percent free PSA and PSA transition zone density provide an additional diagnostic benefit over total PSA.
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