Biopsy-all strategy in patients with a renal mass: simulation of a randomised controlled trial

Abstract

Objectives: To investigate the clinical benefit and cost-effectiveness of a renal biopsy (RB)-all strategy for patients with a renal mass, as in renal cancer the indication for upfront surgery (SUR) without previous RB invariably results in the overtreatment of patients with benign histology.

Patients and methods: A total of 1729 patients with clinical (c)T1-2 cM0 renal mass treated with SUR were included. To simulate a randomised clinical trial comparing patients who underwent SUR vs RB and subsequent treatment, a random binary variable assigned patients to Arm a-SUR and Arm b-RB. In Arm a-SUR, patients are all treated with SUR; postoperative complications and costs are those recorded after surgery. In Arm b-RB, we have assumed an 8-20% uncertain RB histology rate and a 0.07% RB-related complication rate to build our simulation model. Patients are selected for RB and subsequently for surgery in case of malignant or uncertain RB histology; complications are those recorded after surgery in case of malignant or uncertain RB histology, but 0% in case of benign histology. The outcomes of the study were the rate of SUR avoided, the rate of Clavien-Dindo Grade specific complications avoided, and the net difference in per-patient cost in Arm b-RB relative to Arm a-SUR. In all, 10 000 individual iterations of the simulation model were performed and among all iterations, the median and 95% confidence intervals were computed.

Results: If a RB-all strategy is implemented, the expected rate of SUR avoided is 6.7%. The rate of overall, Clavien-Dindo Grade >II, and Clavien-Dindo Grade >III complications avoided is 3.0%, 2.5%, and 0.5%, respectively, and the average net difference in per-patient cost was -$840 (US dollars).

Conclusions: The non-selective use of RB in patients with a renal mass avoids a significant number of SUR, a marginal but existing number of complications, and is associated with decreased healthcare expenditures.

Keywords: benign renal mass; randomised clinical trial; renal biopsy; renal cell carcinoma; simulation.