Partial nephrectomy after a period of active surveillance: Are perioperative and pathology outcomes worsened compared to immediate surgery?

Introduction: Active surveillance (AS) is a viable strategy for managing small renal masses (SRMs) in lieu of immediate surgery, but concerns persist regarding its impact on delayed partial nephrectomy (PN) outcomes. We aimed to compare perioperative and pathological outcomes of patients initially on AS for SRMs, later undergoing PN, against those undergoing immediate PN. Materials and methods: Data were extracted from a prospective institutional database (January 2018-September 2023) for patients with cT1a renal masses. Only malignancies confirmed at final pathology were included. Baseline patient and tumor characteristics and the time from AS enrollment to PN were recorded. Surgical, renal functional, and final pathology outcomes were analyzed, including histology, tumor size, pT stage, upstaging rate, and positive surgical margins. Predictors of upstaging were identified using logistic regression models. Results: Analysis included 356 patients: 307 immediate PN and 49 deferred PN after a median of 18 months in AS. Groups had comparable baseline characteristics; no significant differences emerged in surgical and postoperative outcomes. Final pathology revealed no significant disparities in tumor size, histology, positive margins, or upstaging, though pT stage distribution differed (2.4 % versus 4.3 % for pT3a, immediate versus deferred, p = 0.04). Univariable analysis identified RENAL Score (OR 1.29, 95 % C.I. 1.09-1.53, p = 0.003) and clinical tumor size (OR 1.16, 95 % C.I. 1.10-1.22, p < 0.01) as upstaging predictors, confirmed by multivariable analysis (p < 0.01). Conclusion: Our comparative analysis found no worsened perioperative or adverse pathological outcomes in patients with deferred PN, supporting the safety of this approach in managing SRMs, at least as an initial option.