Renal mass biopsy: A strategy to reduce associated costs and morbidity when managing localized renal masses

Introduction and objectives: Renal mass biopsy (RMB) has not been widely adopted in evaluating small renal mass due to concerns for safety, efficacy, and its perceived lack of consequence on management decisions. We assess the potential cost savings and morbidity avoidance of routine RMB on cT1 renal masses undergoing robotic-assisted partial nephrectomy (RAPN).

Methods: We identified n = 920 consecutive RAPN pT1 renal masses and n = 429 consecutive RMBs for cT1 renal masses over 12 years. Using a novel pathological-based risk classification system for cT1 renal masses, we evaluated the morbidity and costs of our RAPN and RMB cohorts. We then define four clinical scenarios where RMB could potentially delay and/or avoid intervention in our pT1 RAPN cohort and model potential complications prevented and cost savings utilizing common clinical scenarios.

Results: Using our risk stratification system in RAPN patients, final histology was classified as benign in n=174 (18.9%) cases, very low-risk (n = 62 [7%]), low-risk (n = 383 [42%]), and high-risk (n = 301 [33%]), respectively. We identified n = 116 (12.6%) Clavien graded peri-operative complications. In our RMB patients, 120 (27.9%), 17 (3.9%), 240 (55.9%), 52(12.1%) were benign, very low, low and high-risk tumors. The median total direct cost for RAPN was $6955/case compared to $1312/case for RMB. If we established a primary goal to avoid immediate extirpative surgery in benign renal tumors, in the elderly (>70 y) with very low-risk tumors and/or those with high renal functional risks (≥ CKD3b), or competing risks (ASA ≥ 3), RMB could have reduced direct costs by approximately 20% and avoided n = 39 Clavien graded complications, seven readmissions, three transfusions, and two returns to the OR. With the additional cost of performing RMB on those not initially biopsied, the net cost saving would be approximately $1.2 million with minimal added complications while still treating high-risk tumors.

Conclusions: Routine RMB before intervention results in cost-saving and complication avoidance. Given the limitations of biopsy, shared decision-making is mandatory. Biopsy should be considered prior to intervention in at-risk populations.