Active surveillance for small renal masses in elderly patients does not increase overall mortality rates compared to primary intervention: a propensity score weighted analysis.

BACKGROUND To test the effect of active surveillance (AS) versus primary intervention (PI) on overall mortality (OM) in elderly patients diagnosed with SRM. METHODS Elderly patients (75 years or older) diagnosed with SRMs (< 4cm) and treated with either PI [i.e. partial nephrectomy or kidney ablation] or AS between 2009 and 2018 were abstracted from the REnal SURGery in the Elderly (RESURGE) and Delayed Intervention and Surveillance for Small Renal Masses (DISSRM) datasets, respectively. OM rates were estimated among groups with Kaplan Meier method and Cox proportional hazards regression models after applying inverse probability of treatment weighting (IPTW). Multivariable logistic regression model was used to estimate IPTW. Covariates of interest were those unbalanced and/or significantly correlated with the treatment choice or with OM. RESULTS A total of 483 patients were included; 121 (25.1%) underwent AS. 60 patients (12.4%) died. Overall, 6.7% of all deaths were related to cancer. IPTW-Kaplan Meier curves showed a 5-year overall survival rates of 70.0 ± 3.5% and 73.2 ± 4.8% in AS and PI groups, respectively (IPTW-Log-rank p-value=0.308). IPTW-Cox regression model did not show meaningfully increased OM rates in AS group (HR=1.31, 95% CI: 0.69-2.49). CONCLUSIONS AS represents an appealing treatment option for very elderly patients presenting with SRM, as it avoids the risks of a PI while not compromising the survival outcomes of these patients.