UC Irvine

Importance: Prostate cancer remains as one of the most common malignancies in men in the United States. A substantial portion of men experience a biochemical recurrence (BCR) following radical prostatectomy (RP). Salvage surgeries, such as pelvic lymph node dissection (sPLND) and pelvic mass resection (sPMR) are utilized as potential interventions in eligible patients with BCR. However, the factors that predict success of salvage surgeries remain largely unknown.

Objectives: This study aims to investigate the utility of Prostate-specific Antigen doubling time (PSADT) kinetics in predicting salvage surgery success, defined as no need for further treatment post-salvage surgery. In patients who failed and required subsequent treatment, we aim to assess the utility of multiple dimensions of PSA kinetics in predicting the time to treatment post-salvage surgery.

Methods: A retrospective analysis of data from 32 patients with BCR post-RP who underwent salvage surgery was conducted. PSADT graphs were constructed for each patient to represent the pre- and post-salvage periods. A smoothing algorithm was applied to the data to refine PSADT calculation and analysis. The primary independent variable was the average PSADT rate of change over the one-year period pre-salvage surgery. The secondary variables included the instantaneous PSADT rate pre-salvage, pre-salvage PSADT, pre-salvage PSA, and post-salvage PSADT rate. The cohort was stratified into two groups: salvage surgery success (N=12) and salvage surgery failure (N=20). Two-tailed independent t-tests, chi-squared analyses, and linear regression analyses were utilized to compare and analyze our data.

Results: There were no statistically significant differences between the salvage surgery success and failure groups (Table 1-2). Additionally, none of the univariate or multivariate linear regression models were able to identify statistically significant predictors of salvage surgery success in our primary analysis. Subset analysis of the failure group also failed to identify any significant predictors of time to post-salvage surgery treatment.

Conclusion and Relevance: The study did not yield significant predictors of salvage surgery success or time to post-salvage surgery treatment, within the context of PSADT kinetics. This speaks to the complexity and challenges associated with using PSA kinetics alone in predicting salvage surgery outcomes. Additionally, this study highlights the need for studies with larger cohorts that integrate advanced analytical tools to create more refined predictive models. Future studies exploring the general applicability of quantified PSADT rates in post-RP treatment decision-making are warranted.