COST-EFFECTIVENESS ANALYSIS OF PERCUTANEOUS RENAL MASS BIOPSY TO GUIDE THE MANAGEMENT OF SMALL RENAL MASSES

Tuesday, January 7, 2014
Poster Board # P2-4

Jeffrey J. Leow, MBBS, MPH and Steven L. Chang, MD, MS, Brigham and Women's Hospital, Boston, MA, Boston, MA

   Purpose: The majority of localized solid renal tumors are small renal masses (SRM, 4cm) of which 15%-30% are benign.  Percutaneous renal mass biopsy (RMB) is an optional pre-operative evaluation that can potentially identify benign lesions to avoid unnecessary treatment.  We performed a cost-effectiveness analysis to determine the utility of RMB to guide management decisions for SRM.

   Methods: We developed a decision-analytic model estimating the costs and benefits of RMB, compared to immediate curative-intent therapies, to inform the decision for the following treatments: percutaneous/laparoscopic ablation, open/laparoscopic partial nephrectomy (PN), and open/laparoscopic radical nephrectomy (RN). Using published literature, we modeled a 15% non-diagnostic rate, 97.5% sensitivity, 91.2% specificity and 0.01% complication rate. RMB showing malignancy or a non-diagnostic biopsy led to treatment; the finding of a non-malignant SRM led to active surveillance. Our base case was a healthy 65-year old patient with an asymptomatic unilateral 3cm SRM. Outcomes were measured in quality-adjusted life-years (QALY) and 2012 US$, respectively. We used a societal perspective, lifetime horizon, 3% discount rate, 3-month cycle length, and a $50,000/QALY willingness-to-pay threshold.  Alternative clinical scenarios were assessed with sensitivity analysis.

   Results: In the base case scenario, RMB was the cost-effective strategy for all patients considering RN options, while it was not cost-effective to guide the management for patients considering PN or ablative options.  The open and laparoscopic approaches for PN and RN did not impact the utility for RMB.  For RN, sensitivity analyses showed that RMB remained cost-effective across a wide range of tumor sizes, patient ages, and healthy states.  In contrast, RMB prior to PN and laparoscopic ablation became the cost-effective strategy for smaller tumors (<2.5cm), younger patients (<60 years), or less healthy individuals (>5% risk of peri-operative mortality).  For patients planning for percutaneous ablation, RMB was only cost-effective among younger patients (<60 years) with SRM <2cm in size.  The results were primarily driven by the risks for procedural complications and post-operative chronic kidney disease.

   Conclusion: For all patients with a SRM considering RN, RMB is recommended. Among patients with a SRM planning for PN or laparoscopic ablation, RMB is recommended for patients <60-years old, with SRM <2.5cm, or poor health.  For patients electing for percutaneous ablation, RMB is only recommended for patients <60-years old with a SRM <2cm.

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