Analysis of guideline recommended use of renal mass biopsy and association with treatment.

Renal mass biopsy (RMB) may not be indicated when the results are unlikely to impact management, such as in young and/or healthy patients and in elderly and/or frail patients. We analyzed the utility of RMB in three patient cohorts stratified by age-adjusted Charlson comorbidity index score (ACCI). We identified patients with cT1a renal tumors in the National Cancer Database from 2004-2014. We combined age and Charlson-Deyo scores to identify young and/or healthy patients ('healthy-ACCI'), elderly and/or frail patients ('frail-ACCI'), and a reference cohort. We performed multivariable logistic regression to identify predictors of RMB and treatment. We evaluated the impact of RMB on management by analyzing the proportion of high-grade disease on final pathology as a surrogate for risk stratification. We identified 36,720 healthy-ACCI, 2,516 frail-ACCI, and 18,989 reference-ACCI patients. Healthy-ACCI patients were less likely to undergo RMB (7.5% versus 10.8%; p < 0.001) while frail-ACCI patients underwent RMB at similar rates (11.8% versus 10.8%; p = 0.14) compared with reference-ACCI patients. On multivariable logistic regression, in both healthy-ACCI and frail-ACCI patients, RMB was associated with decreased odds of surgical treatment, and increased odds of ablation and surveillance (all p < 0.01). In the frail-ACCI patients, higher grade disease at surgery was identified in the RMB cohort (32.9% versus 23.5%, p = 0.05). RMB is performed less frequently in healthy-ACCI patients compared with the reference cohort. RMB is associated with decreased odds of surgical treatment and increased odds of surveillance and ablation in all cohorts. In frail-ACCI patients who underwent surgery, RMB may provide additional risk stratification as these patients had lower rates of low-grade disease.