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Longitudinal modeling of ultrasensitive and traditional prostate-specific antigen and prediction of biochemical recurrence after radical prostatectomy. Sci Rep 2016; 6:36161. [PMID: 27805011 PMCID: PMC5090356 DOI: 10.1038/srep36161] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 10/03/2016] [Indexed: 11/08/2022] Open
Abstract
Ultrasensitive prostate-specific antigen (u-PSA) remains controversial for follow-up after radical prostatectomy (RP). The aim of this study was to model PSA doubling times (PSADT) for predicting biochemical recurrence (BCR) and to capture possible discrepancies between u-PSA and traditional PSA (t-PSA) by utilizing advanced statistical modeling. 555 RP patients without neoadjuvant/adjuvant androgen deprivation from the Turku University Hospital were included in the study. BCR was defined as two consecutive PSA values >0.2 ng/mL and the PSA measurements were log2-transformed. One third of the data was reserved for independent validation. Models were first fitted to the post-surgery PSA measurements using cross-validation. Major trends were then captured using linear mixed-effect models and a predictive generalized linear model effectively identified early trends connected to BCR. The model generalized for BCR prediction to the validation set with ROC-AUC of 83.6% and 95.1% for the 1 and 3 year follow-up censoring, respectively. A web-based tool was developed to facilitate its use. Longitudinal trends of u-PSA did not display major discrepancies from those of t-PSA. The results support that u-PSA provides useful information for predicting BCR after RP. This can be beneficial to avoid unnecessary adjuvant treatments or to start them earlier for selected patients.
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Seikkula H, Syvänen KT, Kurki S, Mirtti T, Taimen P, Laato M, Boström PJ. Role of ultrasensitive prostate-specific antigen in the follow-up of prostate cancer after radical prostatectomy. Urol Oncol 2015; 33:16.e1-16.e7. [DOI: 10.1016/j.urolonc.2014.10.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 09/14/2014] [Accepted: 10/15/2014] [Indexed: 10/24/2022]
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Reply. Urology 2012. [DOI: 10.1016/j.urology.2012.06.082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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McDermed JE, Sanders R, Fait S, Klem RE, Sarno MJ, Adams TH, Diamandis EP. Nucleic Acid Detection Immunoassay for Prostate-Specific Antigen Based on Immuno-PCR Methodology. Clin Chem 2012; 58:732-40. [DOI: 10.1373/clinchem.2011.170290] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Abstract
BACKGROUND
Serum prostate-specific antigen (PSA) concentrations after radical prostatectomy typically become undetectable with the use of current immunometric assay methods. Despite modern surgical techniques, 15%–30% of prostate cancer patients undergoing radical prostatectomy develop a biochemical recurrence during follow-up. Unfortunately, poor analytical sensitivity of standard PSA assays delays biochemical recurrence detection, and because of day-to-day assay imprecision ultrasensitive PSA assays cannot assess PSA kinetics. We developed an immuno-PCR assay for total PSA that has a limit of quantification >10 times lower than current ultrasensitive assays.
METHODS
The 2-site immunometric assay for total PSA employed 2 monoclonal antibodies, one conjugated to a double-stranded DNA label and the other bound to paramagnetic microparticles. After several washing steps, quantification cycles were determined and values were converted to PSA concentrations. We characterized analytical performance and compared accuracy with a commercially available total PSA assay.
RESULTS
The limit of quantification was 0.65 ng/L and the assay was linear in the range of 0.25–152.0 ng/L. Total imprecision estimates at PSA concentrations of 3.8, 24.1, and 69.1 ng/L were <15.2%, <9.4%, and <10.6%, respectively. Recovery of supplemented PSA ranged from 87.5% to 119.2% (mean 100.3%). Dilution recovery ranged from 96.4% to 115.3% (mean 102.3%). There was no high-dose hook effect up to 50 000 ng/L of PSA. Comparison with the commercial PSA assay showed a regression slope of 1.06 and a correlation coefficient of 0.996.
CONCLUSIONS
The analytical characteristics of the assay support the use of this assay for the accurate and precise measurement of serum PSA, even at sub–nanogram-per-liter concentrations.
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Affiliation(s)
- Jonathan E McDermed
- Iris Molecular Diagnostics, a Division of IRIS International, Inc., Carlsbad, CA
| | - Ron Sanders
- Iris Molecular Diagnostics, a Division of IRIS International, Inc., Carlsbad, CA
| | - Stephen Fait
- Iris Molecular Diagnostics, a Division of IRIS International, Inc., Carlsbad, CA
| | - Robert E Klem
- Iris Molecular Diagnostics, a Division of IRIS International, Inc., Carlsbad, CA
| | - Mark J Sarno
- Iris Molecular Diagnostics, a Division of IRIS International, Inc., Carlsbad, CA
| | - Thomas H Adams
- Iris Molecular Diagnostics, a Division of IRIS International, Inc., Carlsbad, CA
| | - Eleftherios P Diamandis
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Department of Clinical Biochemistry, University Health Network
- Department of Laboratory Medicine and Pathobiology, University of Toronto, ON, Canada
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Ultrasensitive versus standard PSA value for doubling times. Nat Rev Urol 2011. [DOI: 10.1038/nrurol.2011.200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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