Optimum PSA reflex-range.

Area of Science:

• Urology
• Oncology
• Biochemistry

Background:

• Prostate-specific antigen (PSA) testing is crucial for prostate cancer detection.
• Percent free PSA (fPSA) improves diagnostic accuracy compared to total PSA alone.
• Previous strategies utilized fPSA testing primarily in the 4-10 ng/ml total PSA range.

Purpose of the Study:

• To evaluate decision strategies for prostate cancer screening using varying cut-off values of fPSA.
• To determine optimal total PSA (tPSA) reflex ranges for fPSA testing.
• To compare these strategies against conventional tPSA testing for biopsy reduction and cancer detection.

Main Methods:

• Retrospective analysis of 807 patients undergoing transrectal ultrasound biopsies.
• Categorization of patients into prostate cancer (CaP) and control groups.
• Calculation of sensitivity, specificity, and likelihood ratios for tPSA and fPSA across different tPSA intervals.

Main Results:

• Cancer patients exhibited significantly higher tPSA and lower fPSA levels.
• The 2-10 ng/ml tPSA reflex range demonstrated optimal results.
• fPSA showed a higher area under the curve (0.7452) than tPSA (0.6267) in the 2-10 ng/ml range (p=0.0059).

Conclusions:

• Expanding the reflex range for fPSA testing enhances its diagnostic utility in prostate cancer detection.
• The optimal strategy identified uses a 22% fPSA cut-off within the 2-10 ng/ml tPSA range.
• This approach maximizes the decrease in unnecessary biopsies while minimizing the number of undetected cancers.