The increasing use of renal tumor biopsy amongst Canadian urologists: When is biopsy most utilized?

The role of renal tumor biopsy (RTB) in the management of small renal masses (SRMs) is progressively being recognized as a tool to decrease overtreatment. While an increasing number of studies assessing its role in diagnostics are becoming available, RTB remains variably used amongst urologists. Many patient-, tumor-, and institution-related factors may influence urologists on whether to perform a RTB to help guide management.

We aimed at identifying factors associated with the use of RTB for localized SRMs within a number of centers contributing data to the Canadian Kidney Cancer information system.

We identified 3,838 patients diagnosed with a localized SRM (≤4 cm) between January 2011 and December 2018. Patients were stratified based on whether a RTB was performed prior to the primary therapeutic intervention. Factors associated with use of RTB were assessed using univariable and multivariable logistic regression models.

A total of 993 patients (25.9%) underwent an RTB. There was an overall increase in RTB use over time (P < 0.001), with patients diagnosed between 2015 and 2018 undergoing more RTB than patients diagnosed between 2011 and 2014 (29.8% vs. 22.2%, respectively; P < 0.001). Patients managed in centers with the highest patient-volume had RTB more frequently than patients managed in low-volume centers. On multivariable analysis, increasing year of diagnosis was significantly associated with more RTB use. Patients treated with surgery underwent RTB statistically less often than patients undergoing thermal ablation (P < 0.001) or managed with active surveillance (P < 0.001). Larger SRMs were associated with more RTB use in patients on active surveillance (P = 0.009), but with less RTB in patients undergoing surgery (P = 0.045).

This large multicenter cohort study reveals an increasing adoption and overall use of RTB amongst Canadian urologists. Patients managed in high-volume centers and those undergoing non-surgical management were associated with greater use of RTB. Tumor size was also associated with RTB use. This study highlights the influence that physician perceptions and clinical factors may have in the decision to use RTB prior to initiating a therapeutic approach.