The impact of age on pathological insignificant prostate cancer rates in contemporary robot-assisted prostatectomy patients despite active surveillance eligibility

BACKGROUND: The aim of this study was to assess insignificant prostate cancer (iPCa) rates after robot-assisted radical prostatectomy (RARP) in contemporary patients who were preoperatively eligible for active surveillance (AS). iPCa indicates no risk of PCa progression. METHODS: We retrospectively analyzed 2837 RARP patients (2010-2019) who fulfilled at least one AS entry criteria set: Prostate Cancer Research International - Active Surveillance (PRIAS), University of California San Francisco (UCSF) (San Francisco, CA, USA), National Comprehensive Cancer Network (NCCN) or University of Toronto, ON, Canada. We utilized four different iPCa definitions: 1) based on pT2 and Gleason Score <= 6 and also cumulative tumorvolume; 2) <= 2.5mL; 3) <= 0.7mL; or 4) <= 0.5mL. For each AS set we tested the rates of iPCa and compared between age <70 vs. >= 70 years. This was complemented by multivariable logistic regression (LRM) predicting iPCa, adjusted for age and clinical AS variables. Finally, within the subgroup who had iPCa, we tested the rate of those who were deemed preoperatively AS ineligible. RESULTS: Between most (PRIAS) and least stringent (TORONTO) AS sets, iPCa was correctly predicted in 70-57%. Similarly, for iPCa definitions 2-4, rates were 59-42%, 34-19% and 27-14%. Senior patients harbored decreased proportions of iPCa. LRM confirmed that advanced age is associated with a lower chance of iPCa. More stringent AS sets lead to higher rates of AS ineligibility, e.g. 53% for PRIAS, despite iPCa. CONCLUSIONS: AS sets show limited accuracy for stricter iPCa definitions, which further declined with advanced age. Greater AS stringency resulted in more AS ineligible patients despite harboring iPCa. In consequence, patients are at risk for overtreatment. Clinicians must consider age and different AS sets that result in highly variable detection rates of iPCa.