Presentation Authors: Christopher Wallis*, Alaina Garbens, Zachary Klaassen, Ronald Kodama, Sender Herschorn, Robert Nam, Toronto, Canada
Introduction: Renal mass biopsy (RMB) in the evaluation of renal masses for assessment of renal cancer is not widely adopted. Data to date are limited to single-institutional case series. We sought to assess complications following RMB and the subsequent association with post-operative complications following partial or radical nephrectomy using a large, population-based cohort.
Methods: We performed a matched retrospective cohort study of patients undergoing RMB from 2003-2015 in Ontario, Canada. We identified all patients undergoing RMB and subsequently compared these individuals to a matched sample of controls from the general population. We further examined those patients who underwent partial or radical nephrectomy and compared these individuals to those undergoing surgery without a history of RMB. Outcomes of interest included mortality, operative and non-operative interventions, hospitalizations and emergency room visits within 30 days of biopsy.
Results: Among 6840 patients who underwent RMB during the study interval, 159 (2.3%) died within 30 days, 257 (3.8%) required operative intervention and 654 (9.6%) required non-operative intervention. Rates of mortality (relative risk 7.95, 95% CI 5.00-12.64; number needed to treat to harm (NNTH) 49, 95% CI 41-59), hospitalization (relative risk 10.40, 95% CI 8.68-12.47; NNTH 6, 95% CI 5-6), and emergency room visits (relative risk 3.37, 95% CI 2.94-3.80; NNTH 9, 95% CI 8-10) were higher among patients who underwent RMB than the general population (p < 0.001 for each). Among 6178 patients undergoing partial and 19,203 undergoing radical nephrectomy, pre-operative RMB was not significantly associated with post-operative complications in multivariable models. However, patients who underwent RMB were significantly less likely to have benign disease on final pathology with a difference of 22.3% (95% CI 19-25%) and 12.0% (95% CI 9-15%) among those undergoing partial and radical nephrectomy, respectively.
Conclusions: In a large, population-based cohort, renal mass biopsy is associated with small, but non-negligible, risk of mortality and other complications. These risks should be balanced with the potential risk of patients undergoing unnecessary surgery for benign disease.
Source of Funding: Ajmera Family Chair in Urologic Oncology