PSA Standardization

Increase Specificity Using PSA Velocity⁸

October 2009

One way to increase the specificity of PSA is to modify how it is interpreted, and evaluate the change in PSA over time (in months or years), termed PSA velocity.  If the patient has metastatic cancer the PSA will change rapidly over time, to a greater extent than if there is localized cancer contained within the prostate or to an even a greater extent compared to a control population or men with BPH.

The National Cancer Comprehensive Network guidelines recommend calculation of PSA velocity over a one year period.  When the total PSA is less than 4, an increase of greater than or equal to 0.35 ng/mL/year is considered suspicious and when the PSA is between 4-10 ng/mL an increase of greater than or equal to 0.75 ng/mL/year is considered suspicious.  Ideally the clinician would use three specimens over an 18 to 24 month period to adequately assess the velocity.

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Jump to section:

• Introduction
• Elevated PSA Result on Screening
• Reasons for Ordering PSA¹
• PSA Screening in the News
• Recommendations for Screening
• Arguments for Screening for Prostate Cancer
• Recommendations for Not Screening
• Arguments Against Screening for Prostate Cancer
• PSA Sensitivity and Specificity
• High-Grade Prostate Cancer is Not Rare When PSA =4.0 ng/mL⁶
• Increase Specificity Using PSA Velocity⁸
• Optimizing Clinical Sensitivity and Specificity: Age/Ethnic Reference Intervals^9,10
• Utilization of Free/Total PSA Ratio¹¹
• Why Aren't PSA Results Interchangeable?
• Development of PSA Standards
• Development of PSA Standards
• Effect of Analytical Bias on Classification Based on Fixed Criteria
• Analytical Difference: Results per 1000 Patients Tested¹³
• Hybritech vs. WHO Standardized Assays^12,14
• Analytical Differences¹⁵
• CAP Proficiency Testing
• WHO 96/670 Total PSA Preparations¹⁶
• WHO Calibration/Concordance at 3.1 ng/mL Cutoff⁵
• WHO Calibration/Concordance at 3.1 ng/mL Cutoff⁵
• WHO Calibration/Concordance at 4.0 ng/mL Cutoff⁵
• Clinical Differences in PSA Screening¹⁴
• The Clinical Difference
• Fixed Thresholds Produce Problems for Biopsy Recommendations
• Effect on "Watchful Waiting"
• Effect on "Watchful Waiting"
• Adding Biological Variability into the Mix
• Futures in Prostate Cancer Testing?
• PSA Testing at Mayo
• Conclusions
• References
• References
• Questions?