Utilization of renal mass biopsy in patients with localized renal cell carcinoma: A population-based study utilizing the National Cancer Database.

Abstract

662 Background: Recent guidelines suggest an increasing role for renal mass biopsy (RMB) in the management of renal cell carcinoma (RCC) prior to ablative therapy and in patients in whom active surveillance (AS) is being considered. Methods: We queried the National Cancer Database for cases of localized (cT1-cT3N0M0) RCC between 2004-2015. Unadjusted temporal trends in receipt of RMB were characterized over the study period based on type of treatment [partial nephrectomy (PN), radical nephrectomy (RN), ablation, and surveillance], tumor size, age and Charlson Comorbidity Index and compared using analysis of variance. Multivariable logistic regression was used to test for the association between patient, tumor and treatment variables and use of RMB. Results: 338,252 patients were analyzed, with 11.9% (40,276) undergoing RMB. Use of RMB increased from 1,586 (7.6%) in 2004 to 5,629 (16.2%) in 2015 (p<0.001). On treatment strategy, use of RMB increased the greatest in association with ablation from 27% to 63% across the study period (p<0.001). On tumor size, use of RMB increased the greatest for tumors 2-4 cm from 9% to 20% (p<0.001). Conversely, utilization of RMB increased proportionally across different age (p=0.17) and comorbidity (p=0.18) groups over time. Multivariable logistic regression revealed that year of diagnosis (OR 1.06; p<0.001), black race (OR 1.04; p=0.02), higher education (OR 1.09; p<0.001) and insured status (OR 1.23; p<0.001) were associated with increased RMB. However, increasing age (p=0.23) and comorbidity (p=0.35) were not. Compared to tumors <2 cm in size, tumors 2-4 cm (OR 1.36; p<0.001), 4-7 cm (OR 1.18; p<0.001) and >7 cm (OR 1.05; p=0.03) were associated with higher RMB. Compared to treatment with RN, treatment with PN was not associated with increased RMB (p=0.92); however, treatment with ablation (OR 10.90; p<0.001) and with surveillance (OR 4.83; p<0.001) were. Conclusions: The largest increase in RMB was associated with ablation treatment. Rates of RMB for tumors <2 cm and for older, sicker patients not undergoing treatment have correspondingly increased less, indicating RMB may not be as highly used for surveillance.