Abstract
Introduction Long-term management of patients undergoing definitive treatment of a small renal mass depends largely on the final pathology. Pre-ablation renal biopsy (PABx) is often the only source of pathology in patients undergoing thermal ablation of a small renal mass. We sought to evaluate patient and tumor characteristics which may play a role in determining the accuracy of a PABx obtained during radiofrequency ablation (RFA). Materials and methods This retrospective study included a review of our prospectively collected database of all laparoscopic and computer tomography guided RFA (LRFA;CTRFA) performed in our center November 2001- July 2013. Three 18-gauge core biopsies were obtained per tumor. Pathology samples were stratified into diagnostic (group 1) and non-diagnostic (ND) (group 2). We used univariate and multivariate analysis to identify potential biopsy result-modifying factors including patient characteristics (age, BMI), biopsy approach (CTRFA versus LRFA), tumor size, orientation, depth and polarity Results A total of 463 treatments in 411 patients were evaluated. Of these, 66% were CTRFA while 34% were LRFA. Mean patient age was 67.4 years (31-88), mean BMI was 28.3 kg/m2 (16.6-47.2) and mean tumor size was 2.6 cm (0.3-5.5). There were a total of 73 (15.8%) ND biopsies. On multivariate analysis CTRFA and medial tumors treated with either CTRFA or LRFA were found to be associated with an increased likelihood of a ND biopsy. Conclusion PABx obtained in patients undergoing CTRFA and from medial tumors treated with either CTRFA or LRFA were more likely to be ND. Future RFA patients should be counseled appropriately. Additional biopsy cores may be required in these subgroups. Further prospective studies are warranted to confirm these findings.