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Methods of calculating prostate-specific antigen velocity
David Connolly1, Amanda Black, Liam J Murray
1Department of Urology, Belfast City Hospital, Belfast, Northern Ireland, United Kingdom. djconn76@hotmail.com
European Urology
|January 2, 2007
Summary
Different methods for calculating prostate-specific antigen velocity (PSAV) yield varying results. Linear regression is recommended for PSAV calculation to improve prostate cancer diagnosis accuracy.
Area of Science:
- Urology
- Oncology
- Biostatistics
Background:
- Prostate-specific antigen velocity (PSAV) is a biomarker used in prostate cancer diagnosis.
- Multiple methods exist for calculating PSAV, potentially leading to discrepancies in results.
- Understanding these differences is crucial for accurate interpretation of PSAV in clinical practice.
Purpose of the Study:
- To compare PSAV calculations using three common methods.
- To evaluate the differences in PSAV results obtained from these methods.
- To assess the predictive value of each PSAV calculation method for prostate cancer diagnosis.
Main Methods:
- Analysis of a population-based database of PSA results.
- Inclusion of men with initial PSA < 10.0 ng/ml and >= 3 PSA tests over >= 18 months.
- Calculation of PSAV using three distinct methods: Linear Regression (LR), First-Last (FL), and Average-End (AE).
Main Results:
- PSAV values differed significantly across the three calculation methods.
- The LR and FL methods demonstrated similar and higher predictive values for prostate cancer diagnosis compared to the AE method.
- Strong agreement was observed between LR and FL (kappa=0.85), with moderate agreement between LR/AE and FL/AE.
Conclusions:
- The method chosen for PSAV calculation significantly impacts results from the same PSA data.
- Linear regression is the preferred method for calculating PSAV due to its superior predictive value.
- The FL method may be adequate for routine clinical use if PSA measurements are sufficiently spaced in time.
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