Active Surveillance versus Immediate Intervention for Small Renal Masses: A Cost-Effectiveness and Clinical Decision Analysis.

PURPOSE

Active surveillance (AS) with the possibility of delayed intervention (DI) is emerging as a safe alternative to immediate intervention for many patients with small renal masses (SRMs). However, limited comparative data exist to inform the most appropriate management strategy for SRMs.

MATERIALS AND METHODS

Decision analytic Markov modeling was performed to estimate the health outcomes and costs of 4 management strategies for 65-year-old patients with an incidental SRM: AS (with possible DI), immediate partial nephrectomy, radical nephrectomy, and thermal ablation. Mortality, direct medical costs, quality-adjusted life-years, and incremental cost-effectiveness ratios were evaluated over 10 years.

RESULTS

The 10-year all-cause mortality was 22.6% for AS, 21.9% for immediate partial nephrectomy, 22.4% for immediate radical nephrectomy, and 23.7% for immediate thermal ablation. At a willingness-to-pay threshold of $100,000/quality-adjusted life-year, AS was the most cost-effective management strategy. The results were robust in univariate, multivariate, and probabilistic sensitivity analyses. Clinical decision analysis demonstrated that the tumor's metastatic potential, patient age, individual preferences, and health status were important factors influencing the optimal management strategy. Notably, if the annual probability of metastatic progression from AS was sufficiently low (under 0.35%-0.45% for most ages at baseline), consistent with the typical metastatic potential of SRMs <2 cm, AS would achieve higher health utilities than the other strategies.

CONCLUSIONS

Compared to immediate intervention, AS with timely DI offers a safe and cost-effective approach to managing patients with SRMs. For patients harboring tumors of very low metastatic potential, AS may lead to better patient outcomes than immediate intervention.