Oncological outcomes in robot-assisted radical prostatectomy: the value of PSA density as a preoperative predictive factor

Abstract

Background: Pretreatment assessment of patients diagnosed with localized prostate cancer (PCa) is essential for therapeutic decision-making. Currently available staging systems based on prostate-specific antigen (PSA), Gleason score, and clinical stage allow for determining the prognostic characteristics of these patients. Several studies have evaluated the preoperative use of prostate-specific antigen density (PSAD) as a prognostic factor for further risk stratification. To date, the role of PSAD in this setting is still an object of debate.

Objectives: The present analysis aimed to assess the predictive potential of PSAD for adverse oncological outcomes after robot-assisted radical prostatectomy (RARP) and to compare its accuracy to preoperative PSA (pPSA).

Design and methods: We retrospectively reviewed 427 patients diagnosed with localized PCa who underwent RARP at a single institution between January 2015 and January 2020. Generating receiver operator characteristic (ROC) curves, calculating areas under the curves (AUCs), and using a linear regression model, we analyzed the association of PSAD and pPSA with postoperative positive surgical margins (PSM), Gleason score ⩾ 7, persistent PSA, and biochemical recurrence (BCR), with a median follow-up of 47 months.

Results: PSAD showed a significant association with PSM (p < 0.0001), PSA persistence (p < 0.0001), and Gleason ⩾ 7 (p < 0.0001), without being statistically significant in predicting BCR (p = 0.098). The predictive value of PSAD was comparable to pPSA for outcomes of PSA persistence (AUC 0.727 versus 0.771) and Gleason ⩾ 7 (AUC 0.683 versus 0.649).

Conclusion: PSAD is a predictive factor for postoperative oncological outcomes of PSM, Gleason score ⩾ 7, and persistence of PSA. Despite the need for further studies, PSAD could be useful as a prognostic parameter in conjunction with established staging systems.

Keywords: oncological outcomes; prostate cancer; prostate-specific antigen; prostate-specific antigen density; robot-assisted radical prostatectomy.

Figure 1.

ROC curves and AUC show the performance of PSAD and pPSA in predicting postoperative outcomes. (a) Comparison of ROC curves and AUC of PSAD (blue line; AUC 0.727) and pPSA (red line; AUC 0.771) for prediction of PSA persistence and (b) comparison of ROC curves and AUC of PSAD (blue line; AUC 0.683) and pPSA (red line; AUC 0.649) for prediction of Gleason score ⩾ 7. AUC, area under the curve; pPSA, preoperative PSA; PSA, prostate-specific antigen; PSAD, prostate-specific antigen density; ROC, receiver operator characteristic.