Increasing Biopsy Utilization for Renal Cell Carcinoma Is Closely Associated With Treatment

ObjectiveTo describe recent temporal trends in biopsy use for renal cell carcinoma and to identify factors associated with biopsy.Materials and MethodsRenal cell carcinoma diagnoses from 2003 to 2011 were identified using the National Cancer Data Base. Cases were classified by traditional (clinical stage T4, N1, or M1, or history of other malignancies) or expanded biopsy indications. Time trends were plotted, and multivariate analysis was performed to identify factors associated with biopsy.ResultsOf 171,406 eligible patients, we identified 21,019 patients (12.3%) who were biopsied. We observed a significant increase in biopsy usage with time for both the traditional (range, 16.7%-20.6%) and expanded (range, 6.9%-10.9%) subgroups (P < .01 for the trends). By the end of the study period, expanded indications accounted for most biopsies. By far, eventual treatment was the strongest factor associated with biopsy utilization for either subgroup. Compared with patients treated with partial nephrectomy, the odds of being biopsied were 2.7-4.3, 6.0-9.8, 14.6-23.0, and 3.0-4.4 times higher for patients managed with observation, cryoablation, radiofrequency ablation, or chemotherapy (including targeted therapy), respectively (P < .01). In the expanded-indications subgroup, other factors significantly associated with biopsy included sex, race, income, insurance, travel distance, case volume, region, and tumor size (P < .01 for all). Other significant factors in the traditional-indications subgroup were income, region, and Charlson score (P < .01 for all).ConclusionIn recent years, renal cell carcinoma biopsy has been increasingly used in patients with traditional and expanded indications. Its use is strongly associated with treatment and treatment-related factors.