TY - JOUR
T1 - Proenzyme PSA for the early detection of prostate cancer in the 2.5-4.0 ng/ml total PSA range
T2 - Preliminary analysis
AU - Sokoll, Lori J.
AU - Chan, Daniel W.
AU - Mikolajczyk, Stephen D.
AU - Rittenhouse, Harry G.
AU - Evans, Cindy L.
AU - Linton, Harry J.
AU - Mangold, Leslie A.
AU - Mohr, Phaedre
AU - Bartsch, Georg
AU - Klocker, Helmut
AU - Horninger, Wolfgang
AU - Partin, Alan W.
N1 - Funding Information:
This study was partially supported by Hybritech Beckman Coulter, Inc. and by National Cancer Institute Early Detection Research Network Grant No. CA 8623-02.
PY - 2003/2/1
Y1 - 2003/2/1
N2 - Objectives. To determine the clinical utility of using proenzyme prostate-specific antigen (pPSA) for early detection of prostate cancer in the 2.5 to 4.0 ng/mL total PSA range. pPSA, the precursor form of PSA that contains a 7 amino acid leader peptide, and truncated forms such as [-2]pPSA and [-4]pPSA can be measured in serum by research immunoassay. Methods. Archival serum from 119 men (noncancer, 88; cancer, 31), obtained before biopsy and in the total PSA range of 2.5 to 4.0 ng/mL, were assayed for total PSA, free PSA (fPSA), and pPSA. pPSA was defined as the sum of the [-2], [-4], and [-7] forms, and the percent pPSA (%pPSA) was defined as pPSA/fPSA. Results. pPSA averaged 4.6% ± 0.4% (SEM) of total PSA and 39.3% ± 3.5% of fPSA. PSA and %fPSA values were similar between the noncancer and cancer groups, and %pPSA tended to be higher in the cancer group (50.1% ± 4.4%) compared with the noncancer group (35.5% ± 6.7%; P = 0.07). Using receiver operating characteristic analysis to assess clinical utility, the area under the curve for %pPSA was 0.688 compared with 0.567 for %fPSA. At a fixed sensitivity of 75%, the specificity was significantly greater for %pPSA at 59% compared with %fPSA at 33% (P <0.0001). Conclusions. In the 2.5 to 4.0 ng/mL total PSA range, 75% of cancers can potentially be detected with 59% of unnecessary biopsies being spared using %pPSA; use of %fPSA would result in sparing only 33% of unnecessary biopsies. A large prospective clinical trial is needed to confirm these preliminary findings.
AB - Objectives. To determine the clinical utility of using proenzyme prostate-specific antigen (pPSA) for early detection of prostate cancer in the 2.5 to 4.0 ng/mL total PSA range. pPSA, the precursor form of PSA that contains a 7 amino acid leader peptide, and truncated forms such as [-2]pPSA and [-4]pPSA can be measured in serum by research immunoassay. Methods. Archival serum from 119 men (noncancer, 88; cancer, 31), obtained before biopsy and in the total PSA range of 2.5 to 4.0 ng/mL, were assayed for total PSA, free PSA (fPSA), and pPSA. pPSA was defined as the sum of the [-2], [-4], and [-7] forms, and the percent pPSA (%pPSA) was defined as pPSA/fPSA. Results. pPSA averaged 4.6% ± 0.4% (SEM) of total PSA and 39.3% ± 3.5% of fPSA. PSA and %fPSA values were similar between the noncancer and cancer groups, and %pPSA tended to be higher in the cancer group (50.1% ± 4.4%) compared with the noncancer group (35.5% ± 6.7%; P = 0.07). Using receiver operating characteristic analysis to assess clinical utility, the area under the curve for %pPSA was 0.688 compared with 0.567 for %fPSA. At a fixed sensitivity of 75%, the specificity was significantly greater for %pPSA at 59% compared with %fPSA at 33% (P <0.0001). Conclusions. In the 2.5 to 4.0 ng/mL total PSA range, 75% of cancers can potentially be detected with 59% of unnecessary biopsies being spared using %pPSA; use of %fPSA would result in sparing only 33% of unnecessary biopsies. A large prospective clinical trial is needed to confirm these preliminary findings.
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U2 - 10.1016/S0090-4295(02)02398-1
DO - 10.1016/S0090-4295(02)02398-1
M3 - Article
C2 - 12597929
AN - SCOPUS:0037319253
SN - 0090-4295
VL - 61
SP - 274
EP - 276
JO - Urology
JF - Urology
IS - 2
ER -