Association between low prostate-specific antigen levels and greater disease progression in high-grade locally-advanced prostate cancer.

ABSTRACT

PURPOSE: In advanced or high-grade prostate cancer (PCa), prostate-specific antigen (PSA) is usually elevated, however, some patients may present with low initial PSA (iPSA) levels. The objective of this study was to evaluate whether different iPSA levels were associated with dissimilar clinical outcomes among men with high-grade PCa and advanced disease after robot-assisted laparoscopic radical prostatectomy (RaLRP). METHODS: This study enrolled 69 PCa patients with initial Gleason score ≥8 and pathologic T-stage ≥3a from April 2012 to December 2018. Patients were stratified into 3 groups based on iPSA levels at diagnosis <5.0, 5.0-9.9, and ≥10.0. The patients' related parameters were compared among these groups. RESULTS: The median follow-up period was 33.1 months (IQR 12.1-48.1). There was no difference in biochemical recurrence (BCR) between the 3 groups (Log-rank test, p = 0.484). We found a higher risk of biochemical recurrence in patients with positive surgical margins (HR 5.04, 95% CI 1.64-15.50, p = 0.005). In addition, patients with low iPSA levels (<5.0 ng/mL) had poor radiographic progression-free survival (Log-rank test, p = 0.001) and a higher risk of disease progression (HR 12.2, 95% CI 1.18-1260.99, p = 0.036) compared with patients with higher iPSA levels (≥10 ng/mL). CONCLUSION: In patients with high-grade locally-advanced PCa, a low iPSA level was associated with a higher risk of disease progression, but not with biochemical recurrence. In this unique population, serum PSA may not be a reliable marker to detect disease progression. Monitoring of these patients may warrant other biomarkers or imaging.