Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0376358 (prostate cancer)
 59,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Bayer Immuno 1 PSA Assay measures total PSA in human serum and demonstrates excellent performance with an interassay CV < or = 3.4% and a biological detection limit of 0.03 microgram/L. No significant interference from common hormonal and chemotherapeutic drugs, kallikrein, prostatic acid phosphatase, and trypsin, or elevated levels of total bilirubin, hemoglobin, triglycerides, and IgG was observed. The 95th percentile values for healthy individuals increased with age from 3.0 micrograms/L for males 50-59 years and 3.3 micrograms/L for males 60-69 years, to 4.6 micrograms/L for males > or = 70 years. Clinical studies with retrospective samples demonstrated correspondence between serial measurements of PSA and clinical outcome for 98% of 159 prostate cancer patients. Clinical sensitivity for patients with clinical evidence of disease, untreated at the time of specimen draw, increased with increasing stage from 77.5-100%. Specificity of 60-70% for BPH and other benign urogenital diseases was consistent with previous findings. Bayer Immuno 1 PSA Assay values for 2131 specimens from healthy subjects and patients with prostate cancer, BPH, and other malignant and nonmalignant diseases correlated well with the Abbott IMx PSA Assay over the range 0.0-6,238 micrograms/L (Y = 1.10 x + 0.02). The Bayer Immuno 1 PSA Assay provides automated ultrasensitive, precise, and equimolar measurement of total PSA in human serum.
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PMID:Bayer Immuno 1 PSA Assay: an automated, ultrasensitive method to quantitate total PSA in serum. 948 72

We conducted a multicenter evaluation of the analytical and clinical performance of the automated Bayer Immuno 1 complexed PSA (cPSA) assay, and compared assay performance to the Bayer Immuno 1 PSA assay. We sought to determine whether measurements of cPSA could be of clinical utility in the management of patients with prostate cancer. Results of the 10-day imprecision across three evaluation sites produced total CV < 2.50% and an analytical sensitivity of 0.02 microgram/L. There was an increased trend in clinical sensitivity for prostate cancer with increasing stage of disease (71-86%). Clinical specificity for patients with benign urogenital disease was 74.8%, and for other nonprostate diseases ranged from 91.1-100%. Retrospective serial monitoring of 155 patients with prostate cancer demonstrated concordance of cPSA measurements to clinical status for 97% of the patients analyzed. Results from the clinical studies using the Bayer Immuno 1 cPSA assay were comparable to results obtained with the Bayer Immuno 1 PSA assay. The Bayer Immuno 1 cPSA assay demonstrates analytical performance and clinical effectiveness in the management of prostate cancer patients during the course of disease and therapy.
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PMID:Multicenter evaluation of the performance and clinical utility in longitudinal monitoring of the Bayer Immuno 1 complexed PSA assay. 1039 26

Prostate specific antigen (PSA) is a glycoprotein found in the epithelial cells of the prostatic duct and acini. PSA is elevated in all four stages of prostate cancer as well as in benign prostatic hypertrophy. We evaluated a new chemiluminescent assay for PSA by comparing this assay with the microparticle enzyme immunoassay for PSA (MEIA) on the AxSYM analyzer (Abbott Laboratories, Abbott Park, IL) and a Hybritech Tandem R assay for PSA. The new chemiluminescent assay is recently available from Bayer Diagnostics (Tarrytown, NY) and can be run using the ACS: 180 Plus analyzer. Precision of the new chemiluminescent assay was evaluated using commercially available controls (Bayer Diagnostics). The within-run and total CVs were 6.4 and 8.7% for the low control (mean: 0.43 microg/L), 1.6 and 5.2% for the next level control (mean:1.94 mg/L), 4.3 and 4.9% for the medium control (mean: 2.10 mg/L), 1.2 and 3.9% for the high control 1 (mean: 11.52 mg/L), and finally 3.2 and 6.9% for the high control 2 (mean: 21.52 mg/L). The spike recovery varied from 94.2 to 109.6% for five different specimens we studied. We also observed excellent dilution recoveries. For example, in the specimen supplemented with 3.02 mg/L of PSA, the dilution recoveries were 102. 1, 104.7, and 103.7% for 1:2, 1:4, and 1:8 dilutions, respectively. We analyzed 113 serum specimens from patients with various concentrations of PSA (range 0.5 mg/L-2040 mg/L) using the new chemiluminescent assay and compared our results with the MEIA and Hybridtech (Tandem-R PSA) assays. Using x axis as the PSA concentrations obtained by the Tandem-R assay and the y axis as the PSA values obtained by the new chemiluminescent assay, we observed the following regression equations: y = 1.04 x -0.19 (r = 0.99, n = 112). One specimen with PSA concentrations of 2040 microg/L by the MEIA and 2156 microg/L by the chemiluminescent assay was not used for regression analysis. Similarly using x axis as the PSA concentrations obtained by the MEIA assay and y axis as the PSA concentrations obtained by the chemiluminescent assay, we observed the following regression equation: y = 0.88 + 0.02 (r = 0.99, n = 112). We conclude that the new chemiluminescent assay has excellent precision and the results compared well with the existing assays.
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PMID:Performance evaluation of a new chemiluminescent assay for prostate specific antigen. 1090 69

We evaluated the analytical performance and diagnostic utility of complexed prostate-specific antigen (CPSA) and their ratios, complexed-to-total PSA (C/T PSA) and free-to-complexed PSA (F/C PSA), in comparison with the total PSA (TPSA) and free-to-total PSA ratio (F/T PSA) as means of diagnosing prostate cancer (PC). Samples (n=101) were drawn from men with no evidence of malignancy (n=80) and from men with PC (n=21) at biopsy. For determination of the F/T PSA ratio, the DPC Immulite-2000 method was used; and the Bayer Immuno-1 CPSA and TPSA assays were used to determine the C/T PSA ratio. The Bayer Immuno-1 CPSA assay provides accurate and precise CPSA values in human serum. The performance of the different forms and ratios was compared using receiver operating characteristic curve analysis. CPSA had the greatest area under the curve (AUC, 0.689) although it was not statistically different from the other parameters. A cut-off value of 4.66 ng/ml for CPSA provided a specificity of 38% and a sensitivity of 93%. The F/C PSA ratio maintained a sensitivity of 93% and had an increased specificity of 41%. The measurement of CPSA provides a slight increase in specificity compared with the use of the TPSA in the early detection of prostate cancer.
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PMID:Free and complexed prostate-specific antigen (PSA) in the early detection of prostate cancer. 1134 44

Molecular forms of prostate-specific antigen (PSA) improve the differentiation between benign prostatic hyperplasia (BPH) and prostate cancer (PCa) in men with total PSA concentrations between 4 and 10 microg/l. To evaluate the diagnostic utility of free PSA (fPSA) and complexed PSA forms for identification of men with PCa in the low PSA range of <4 microg/l, total PSA (tPSA), alpha(1)-antichymotrypsin complexed PSA (PSA-ACT) and fPSA (Roche Elecsys [ES] system) as well as tPSA and complexed PSA (cPSA) (Bayer Immuno 1 system) were measured in archival serum samples from 31 untreated patients with PCa, 66 patients with BPH, and 90 men without prostatic disease. The median ratios of fPSA/tPSA, PSA-ACT/tPSA and cPSA/tPSA were significantly different between patients with BPH and PCa (27.2 vs. 19.4%, 64 vs. 88%, 77.2 vs. 88.2%, p < 0.05). No associations between PSA forms and tumor stage and grade were found. Analysis of the receiver operating characteristic curves showed that these ratios could discriminate better between BPH and PCa patients than determination of the analytes tPSA, fPSA, cPSA and PSA-ACT alone. The use of one of the ratios would have eliminated roughly half of the unnecessary biopsies in this study. The ratios should be considered as potential tools to increase the selectivity of PCa detection at low PSA concentration. The ratios fPSA/tPSA and cPSA/tPSA can be determined using commercially available assays so that one of these ratios could be preferred instead of PSA-ACT determination. The ratios could be useful in assessing the risk of PCa in the individual and therefore in deciding on prostate biopsy for final diagnosis.
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PMID:Molecular forms of prostate-specific antigen in serum with concentrations of total prostate-specific antigen <4 microg/L: are they useful tools for early detection and screening of prostate cancer? 1147 92

This article presents the current reports of complexed prostate-specific antigen (PSA) aimed for the enhancement of prostate cancer detection. Further studies are needed to ascertain the variability of complexed PSA. Comparisons of percent free PSA, potential additive value of alpha(1)-antichymotripsin-bound PSA (PSA-ACT) and Bayer complexed PSA (cPSA) remains controversial in men with intermediate elevated total PSA concentration. Volume-referenced complexed PSA (PSA-ACT and cPSA) can enhance prostate cancer detection. Preliminary results show that PSA-alpha(2)-macrobloblin (PSA-a(2)M) and PSA-alpha(1)-protease inhibitor (PSA-API) are promising assays for improving cancer detection.
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PMID:Complexed prostate-specific antigen improvement in detecting prostate cancer. 1208 74

Over time, the parameters commonly used to predict pathological stage in men with localized prostate cancer have changed, and there is now little stratification in pretreatment prostate-specific antigen (PSA) concentrations, clinical stages, and biopsy Gleason scores. This prospective study evaluated the utility of complexed PSA (cPSA ) for predicting organ-confined disease in a contemporary series of subjects. The age range of the 420 men was 39 to 72 years (58.2 +/- 6 years). Specimens were collected before radical prostatectomy, and total and free PSA (Hybritech Tandem assays, Beckman Access; Beckman Coulter, Inc., Brea, CA) and total and cPSA (Bayer Immuno 1; Bayer Corporation, Tarrytown, NY) were measured. Pathologic stage was determined from the prostatectomy specimen. Of the 420 men, 316 (75%) had organ-confined disease, and 104 (25%) had non-organ-confined disease (20.7% had extraprostatic extension, 2.6% had seminal vesicle involvement, and 1.4% had positive lymph nodes). Prebiopsy Gleason score distribution was as follows: organ-confined organ-confined, 6 (87%) and 7 (10%); non-organ-confined, 6 (66%) and 7 (30%). Of patients with organ-confined disease, 75% had clinical stage T1c disease compared with 56% for non-organ-confined disease. Using univariate logistic regression, the following variables predicted organ-confined disease: biopsy Gleason score, clinical stage, total PSA, percent free PSA, cPSA, percent cPSA (P <0.05). A multivariate model with biopsy Gleason score, clinical stage, and cPSA had a receiver operator characteristic area under the curve of 0.69. Replacing cPSA with total PSA in this model provided similar information. cPSA and total PSA were highly correlated (r = 0.985). In summary, cPSA was equivalent to total PSA in predicting organ-confined disease. Present and future models and nomograms using PSA as an indicator of pathological stage could consider use of cPSA.
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PMID:Complexed prostate-specific antigen as a staging tool for prostate cancer: a prospective study in 420 men. 1238 58

Differences in stability of the free and complexed molecular forms of prostate-specific antigen (PSA) may influence the clinical utility of assays for these forms, as well as the calculated ratios to total PSA (tPSA), such as percent free PSA (fPSA) and percent complexed PSA (cPSA). The objective of this study was to directly compare the short-term stability of fPSA and cPSA under different storage conditions. Specimens (3 with prostate cancer, 3 biopsy-negative without cancer, 2 normal) from 8 men were analyzed at baseline within 2 hours of collection, and at 4 hours, 8 hours, 24 hours, 48 hours, and 1 week after storage at room temperature, 4 degrees C, or -20 degrees C. Serum specimens were analyzed in duplicate on the Bayer Immuno 1 analyzer (tPSA, cPSA) and on the Beckman Coulter Access analyzer (tPSA, fPSA Tandem assays). Baseline tPSA values ranged from 0.7 to 62.0 ng/mL, with a median of 7.9 ng/mL (Immuno 1). Overall, all forms of PSA were stable up to 24 hours at the 3 temperatures, with the exception of fPSA and percent fPSA, which decreased when stored at 4 degrees C. After 1 week, tPSA levels decreased when stored at room temperature and at 4 degrees C, as did cPSA stored at room temperature. Over the 7 days, percent cPSA was stable at room temperature, but increased at 4 degrees C. There were no significant changes in any PSA form or calculated ratio with storage at -20 degrees C for up to 1 week. In summary, in the short term (<1 week), fPSA is less stable with storage than tPSA or cPSA in a time- and temperature-dependent fashion. Thus, specimen handling should be considered when interpreting PSA results. It is recommended that specimens not analyzed the same day (within 8 hours of collection) be stored frozen at -20 degrees C.
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PMID:Short-term stability of the molecular forms of prostate-specific antigen and effect on percent complexed prostate-specific antigen and percent free prostate-specific antigen. 1238 59

Complexed PSA (cPSA) has been shown to improve specificity in the detection of prostate cancer over that of total PSA (tPSA) testing in men with tPSA values greater than the cutoff value of 4.0 ng/mL. However, recent studies have reported a 25% incidence of prostate cancer in men with tPSA values in the 2.5- to 4.0-ng/mL range. We performed a multicenter study of cPSA in a population of men who underwent prostate biopsies because of elevated PSA levels or abnormal digital rectal examination (DRE). As part of this study, we sought to assess the clinical value of cPSA in comparison to tPSA, the free/tPSA ratio (f/tPSA) and the complexed/tPSA ratio (c/tPSA) in early detection of prostate cancer in men with tPSA values in the range of 2 to 4 ng/mL. The study was performed at 7 centers. Sera were drawn from men who underwent biopsy procedures consisting of >10 prostate tissue cores. Receiver operating characteristic (ROC) analysis was performed from the results of patients with tPSA values in the range of 2 to 4 ng/mL, including men with suspicious as well as unremarkable findings on DRE. Sera were collected and tested with the Bayer tPSA and cPSA assay and the Beckman free PSA and tPSA assays. ROC analysis was performed for all samples in the 2- to 4-ng/mL PSA range. At biopsy, 158 men had no evidence of malignancy and 57 (26.5%) were diagnosed with prostate cancer. ROC analysis indicated that the area under the curve (AUC) for cPSA was 0.64, which was statistically significantly greater than that achieved for tPSA (AUC, 0.57; P <0.0001). The AUC for f/tPSA and c/tPSA were 0.60 and 0.63, respectively, which was not statistically significantly different from that of tPSA or cPSA (P >or=0.252). A cutpoint of 2.5 ng/mL for tPSA and 2.1 ng/mL for cPSA provided a specificity of 20.3% and 34.2%, respectively, and sensitivity levels of 86%. Using cutpoints of 25% for f/tPSA and 74% for c/tPSA provided a specificity of 11.0% and 21.5%, respectively, and sensitivity levels of 97%. In all, >92% of the cancers treated with radical prostatectomy were organ confined, and the histologic grading of the tumors ranged from moderately to poorly differentiated with Gleason scores from 5 to 9. These data confirm that there is a high incidence of clinically significant prostate cancer in men with tPSA levels <4.0 ng/mL. Measurement of cPSA proved useful in stratifying men with tPSA values in the 2- to 4-ng/mL range into high- and low-risk groups for prostate cancer. The use of cPSA as a single test was found to enhance detection of prostate cancer over that of testing with tPSA and PSA ratios in men with tPSA values in the range of 2 to 4 ng/mL.
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PMID:Complexed prostate-specific antigen for early detection of prostate cancer in men with serum prostate-specific antigen levels of 2 to 4 nanograms per milliliter. 1238 60

Age-specific prostate-specific antigen (PSA) cutoffs were previously suggested and were found to miss significant cancers in older men. We assessed the influence of an age-adjusted PSA cutoff to optimize the diagnostic performance (sensitivity and specificity) of complexed PSA (cPSA) and total PSA (tPSA) in the differentiation of benign disease from prostate cancer using a contemporary referral patient cohort. The cPSA and tPSA values were determined using the Bayer Immuno 1 system. The diagnostic utility of tPSA and cPSA was assessed using a diverse contemporary test population consisting of sera prospectively collected between June 1999 and October 2000 from 3597 men who recently underwent a systematic biopsy by urologists in clinical practices throughout the United States. This contemporary patient sample had biopsy diagnoses of either no evidence of malignancy (NEM; N = 2189) or prostate cancer (n = 1408). All serum samples had tPSA values between 2.0 and 20.0 ng/mL. The mean tPSAs (ng/mL) for the NEM and prostate cancer groups were 7.1 +/- 3.2 and 7.3 +/- 3.3, respectively (P = 0.026). The mean cPSAs (ng/mL) for the NEM and prostate cancer groups were 5.6 +/- 2.7 and 6.0 +/- 2.9, respectively (P <0.001). As the tPSA increased from 2.0 to 10.0 ng/mL, the cancer detection rate remained relatively constant at approximately 39% when evaluated using increments of 2.0 ng/mL for tPSA. For fixed sensitivities of 80%, 85%, 90%, and 95%, as the age range increased (45 to 59, 60 to 69, 70 to 79, >or=80), the tPSA and cPSA assay cutoffs required to sustain the specified sensitivity level markedly increased, with the exception of the 95% sensitivity level, where the cutoffs only slightly increased between the age ranges of 45 to 69 and >or=70. Overall, cPSA showed a marginal improvement in specificity versus tPSA across all age groups at all sensitivity levels. In this community referral population, the cancer detection rate remained fairly constant over the tPSA range of 2.0 to 20.0 ng/mL. This study demonstrated that to maintain a given sensitivity level for cPSA and tPSA in the age ranges studied, continuous upward adjustment of the cutoffs was required as age increased.
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PMID:Impact of age on total and complexed prostate-specific antigen cutoffs in a contemporary referral series of men with prostate cancer. 1238 63


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