Poster, Podium & Video Sessions
Presentation Authors: Andrew McIntosh*, Pranav Parikh, Anthony Tokarski, Eric Ross, David Chen, Richard Greenberg, Alexander Kutikov, Marc Smaldone, Rosalia Viterbo, Robert Uzzo, Philadelphia, PA
Introduction: We review our large singe center experience with active surveillance (AS) for cystic renal masses (CRMs), focusing on patients with ≥ 5 years (yrs) of follow-up.
Methods: We queried our prospectively maintained kidney cancer database (n = 2574) to identify patients with CRMs enrolled on AS. Estimated tumor volume (ETV) at presentation was calculated using a standard formula and linear growth rate (LGR) was evaluated. Wilcoxon rank sums were used to assess for demographic differences in growth rates and crossover to delayed intervention (DI). Kaplan-Meier curves were used to evaluate pts who crossed over to DI. A sub-set analysis was performed of patients with ≥5 years follow-up and no cross-over to DI.
Results: Of 601 AS patients, we identified 196 patients with CRMs enrolled in AS (64.3% male, median age 64.3 yrs, and mean ETV of 39.1 cm3). The median follow-up for the CRM cohort was 59.7 months. 48 patients (24%) with cystic renal masses crossed over to DI with a median time to DI of 16.7 months (IQR 10.8 - 27.7 months). When compared to solid masses, patients with CRMs (33.9% vs. 23.3%, p < 0.016) were less likely to proceed to treatment. The majority of patients (64%) with CRMs who crossed over to DI did so within 2 years. Younger patients (57.2 vs. 64.4 yrs, p < 0.001) were more likely to crossover to DI. Mean change in ETV was 5.8 cm3/yr and mean LGR was 2.6 mm/yr. Mean change in ETV of cystic masses was slower than solid masses (5.8 vs. 11.4 cm3/yr, p <0.04). A majority of patients (95.4%) were still alive at 60 months follow-up. A subset of 37 patients with CRMs had ≥5 years of follow-up without crossing over to DI. All of the patients were alive and only one patient developed distant metastasis. Mean LGR for this sub-set was 0.1 mm/yr.
Conclusions: Active surveillance with or without delayed intervention is a successful strategy in well selected patients with localized cystic renal masses. Most patients who cross over into DI are likely to do so within the first 2 years on AS. Metastasis and death are rare events in a well selected group of patients. Cystic masses grow more slowly and are less likely to proceed to intervention when compared to solid masses.
Source Of Funding: None