Purpose: The aim of the study is to evaluate the impact of having a nadir and persistently detectable ultrasensitive prostate-specific antigen (uPSA) between 0.01 and 0.1 ng/ml post-robot-assisted radical prostatectomy (RARP), on future biochemical recurrence (BCR).
Methods: We conducted a retrospective analysis of a prospectively maintained cohort of 1359 men who underwent RARP, between 2006 and 2019. Patients were followed with uPSA at 1, 3, 6, 9, 12, 18, 24, 30, 36 months and annually thereafter. We included patients with PSA nadir values between 0.01 and 0.1 ng/ml within 6 months of surgery and with at least 2 follow-up measurements within the same range. We divided patients based on their BCR status and analyzed uPSA changes. Multivariable Cox-regression models (CRMs) were used to analyze variables predicting BCR-free survival (BCR-FS).
Results: We identified 167 (12.3%) patients for analyses, with a mean follow-up time of 60.2 ± 31.4 months. In our cohort, 5-year BCR-FS rate was 86%. Overall, 32 (19.1%) patients had BCR, with a mean time to BCR of 43.7 ± 24.3 months. BCR-free patients had stable mean uPSA values ≤ 0.033 ng/ml, while patients who developed BCR showed a slowly rising trend over time, with a significant difference between groups starting at 9 months (p < 0.02). In multivariable CRMs, a rising uPSA starting at 9 months was an independent predictor of BCR (HR: 2.7; 95% CI 1.6-3.82; p = 0.013).
Conclusion: In the present cohort, our results demonstrated that a considerable number of men have detectable uPSA values ranging between 0.01 and 0.1 ng/ml post-RARP. They can still be followed regularly to avoid patients' anxiety and salvage radiotherapy. Close follow-up is still required.
Keywords: Biochemical recurrence; Prostate cancer; Prostate-specific antigen nadir; Robotic-assisted radical prostatectomy.