LAUSR

PURPOSE We evaluated our experience of a multidisciplinary approach to renal mass biopsy (RMB) for small renal masses (SRM) employing in-office ultrasound (US) guided biopsy by urology (24%), computed tomography (CT) or US biopsy by interventional radiology (IR) (79%), and endoscopic ultrasound-guided biopsy by gastroenterology (GI) (4%). METHODS A single-institution retrospective review of patients who underwent RMB for SRM from May 2013 to August 2019 was conducted. Data regarding patient demographics, tumor characteristics, biopsy technique, histopathology, and management were collected. Diagnostic rates, concordance with final pathology, complications, and outcomes were analyzed. RESULTS Of the 192 biopsies reviewed, 63% biopsies were malignant, 20% were benign, and 17% were non-diagnostic. Based on biopsy results, 71 patients (37%) elected active surveillance. Thirty-eight (20%) patients underwent cryoablation, 56 (29%) underwent partial nephrectomy (PN), 14 (7%) underwent radical nephrectomy (RN) and the remaining patients were treated elsewhere. The rate of surgery for benign pathology after pretreatment RMB was 3%. The concordance rate between biopsy and final pathology was 99% for malignancy, 96% for specific pathology subtype, and 85% for RCC grade. Median time from diagnosis to definitive treatment was 97 days (urology: 76, IR: 110 and GI: 54, p=0.002). Three (1.6%) Clavien I complications were reported. CONCLUSION Our multidisciplinary approach to renal mass biopsy for clinical stage T1a demonstrated favorable safety and diagnostic rates, which effectively directed management strategies and minimized surgery for benign disease. Urologist performed office-biopsies significantly shortened the time from diagnosis to definitive treatment. Our experience with GI EUS biopsy has demonstrated feasibility and safety for tumors that were otherwise not accessible percutaneously.