Utilization of Renal Mass Biopsy for T1 Renal Lesions across Michigan: Results from MUSIC-KIDNEY, A Statewide Quality Improvement Collaborative

Abstract

Background Renal mass biopsy (RMB) has had limited and varied utilization to guide management of renal masses (RM). Objective To evaluate utilization of RMB for newly diagnosed cT1 RMs across diverse practice types and assess associations of outcomes with RMB. Design, setting, and participants MUSIC-KIDNEY commenced data collection in September 2017 for all newly presenting patients with a cT1 RM at 14 diverse practices. Patients were assessed at ≥120 d after initial evaluation. Outcome measurements and statistical analysis Demographics and outcomes were compared for patients undergoing RMB versus no RMB. Clinical and demographic characteristics were summarized by RMB status using a χ 2 test for categorical variables and Student t test for continuous variables. A mixed-effects logistic regression model was constructed to identify associations with RMB receipt. Results and limitations RMB was performed in 15.5% ( n = 282) of 1808 patients with a cT1 RM. Practice level rates varied from 0% to 100% ( p = 0.001), with only five of 14 practices using RMB in >20% of patients. On multivariate analysis, predictors of RMB included greater comorbidity (Charlson comorbidity index ≥2 vs 0: odds ratio [OR] 1.44; p = 0.025) and solid lesion type (cystic vs solid: OR 0.17; p = 0.001; indeterminate vs solid: OR 0.58; p = 0.01). RMB patients were less likely to have benign pathology at intervention (5.0% vs 13.5%; p = 0.01). No radical nephrectomies were performed for patients with benign histology at RMB. The limitations include short follow-up and inclusion of practices with low numbers of RMBs. Conclusions Utilization of RMB varied widely across practices. Factors associated with RMB include comorbidities and lesion type. Patients undergoing RMB were less likely to have benign histology at intervention. Patient summary Current use of biopsy for kidney tumors is low and varies across our collaborative. Biopsy was performed in patients with greater comorbidity (more additional medical conditions) and for solid kidney tumors. Pretreatment biopsy is associated with lower nonmalignant pathology detected at treatment.

Initial Management of Indeterminate Renal Lesions in a Statewide Collaborative: A MUSIC-KIDNEY Analysis

“…15,16 Our data with regard to RMB, similarly, showed its utility and effect on management of the selected patients in whom it was performed. 17 There was a definitive reclassification to benign or malignant histology in 87% of patients with IRLs, with only 5.6% of radiographically IRLs continuing to be categorized as indeterminate after RMB. The overall RMB utilization rate with IRLs was 11.9%, which is lower than the overall rate of 15.5% across all cT1RM in the registry and other reported rates in the literature, further reinforcing the fact that urologists might be underutilizing a tool that can help reduce overtreatment and rates of nonmalignant pathology at surgery.…”

“…The overall RMB utilization rate with IRLs was 11.9%, which is lower than the overall rate of 15.5% across all cT1RM in the registry and other reported rates in the literature, further reinforcing the fact that urologists might be underutilizing a tool that can help reduce overtreatment and rates of nonmalignant pathology at surgery. 13,17,18…”

“…The overall RMB utilization rate with IRLs was 11.9%, which is lower than the overall rate of 15.5% across all cT1RM in the registry and other reported rates in the literature, further reinforcing the fact that urologists might be underutilizing a tool that can help reduce overtreatment and rates of nonmalignant pathology at surgery. 13,17,18 The economic impact of the management of IRLs has not been studied, and few data exist comparing the true cost of immediate treatment to surveillance for cT1RMs. However, hypothetical models have demonstrated active surveillance with the possibility of delayed intervention to be a cost-effective approach in managing small RMs when compared to immediate intervention.…”

Clinical safety and efficacy of microwave ablation for small renal masses

“…RMB rarely precedes surgical therapy, despite prior studies reporting that around 20% of cT1 lesions reveal benign findings on post-surgical pathology reports ( 21 ). In line with prior literature, approximately 20% of patients who underwent concurrent ablation at time of biopsy ultimately had benign pathology, overwhelmingly oncocytoma.…”