The impact of positive surgical margins on salvage radiation or androgen deprivation therapy following radical prostatectomy - a nationwide study

Background: The extent to which positive surgical margins (PSM) affect the risk of subsequent salvage radiation therapy (sRT) or androgen depletion therapy (ADT) following radical prostatectomy (RP) is not well described. Initiation of additional therapies after RP depend on patient preference, individual factors, local guidelines, and life expectancy. The aim of this study was to analyze differences between margin status in risk of subsequent treatment for PCa following RP in a retrospective population-based cohort from Denmark.

Methods: Patients who underwent RP were identified in The Danish Prostate Cancer Registry (DaPCaR). Subsequent sRT and ADT were assessed in uni- and multivariate settings and validated with receiver operating characteristic (ROC).

Results: PSM was associated with an increased risk of sRT (HR = 1.85, p < .001) and receiving ADT (HR:1.39, p = .007). Margin status only had a minor impact on the predictive ability for sRT (area under the curve (AUC): p < .001) and no significant impact for subsequent ADT (AUC: p = 1). Significant inter-institutional difference in the association between PSM with sRT or ADT was observed.

Conclusion: PSM is associated with the risk of sRT and initiation of ADT, however this association is weak. Our results underline that factors beyond tumor characteristics play a major role for initiation of sRT and ADT.