Introduction:

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; renal masses ≤4 cm suspicious for clinical stage T1a renal cell carcinoma). However, limited comparative data exist to inform the most appropriate management strategy for SRMs. Therefore, this study aimed to compare the clinical and economic outcomes of competing management strategies for patients with incidental SRMs, including AS and immediate intervention options.

Methods:

We developed a decision analytic Markov model to estimate the health outcomes and costs of four management strategies for otherwise healthy, asymptomatic 65-year-old patients diagnosed with an incidental SRM, including AS (with possible DI), immediate partial nephrectomy (PN), immediate radical nephrectomy (RN), and immediate thermal ablation (TA). Outcomes assessed included mortality, direct medical costs, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratio (ICER) evaluated over 10 years.

Results:

The 10-year all-cause mortality was 22.6% for AS, 21.9% for immediate PN, 22.4% for immediate RN, and 23.7% for immediate TA. AS was less costly than the immediate intervention strategies. Immediate PN and TA had an ICER of $206,181/QALY and $335,488/QALY versus AS, respectively. Immediate RN was dominated by AS. At a willingness-to-pay threshold of $100,000/QALY, AS was the most cost-effective management strategy (Table). The cost-effectiveness analysis 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 (the age-dependent cutoff was 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 any immediate intervention strategy (Figure).

Conclusion:

Decision analytic modeling shows that 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 such as SRMs <2 cm, AS may lead to better patient outcomes than immediate intervention provided that the decision is appropriately individualized based on patient and tumor characteristics.

Funding: N/A