Abstract No. 515 Renal tumor biopsy following percutaneous cryoablation of renal masses

Abstract

Percutaneous tumor biopsy is recommended prior to percutaneous ablation of renal masses; however, reported complications of hemorrhage in up to 91% of cases in addition to probe crowding in small lesions may negatively affect mass visualization. Post biopsy track seeding is a rare, but biopsy of ablated tissue might decrease the probability. Tumor histology is readily identifiable after freezing. We report our experience of performing renal biopsy following percutaneous cryoablation of solid renal masses in order to assess the safety and feasibility of this technique. From December 2018 to July 2019, 8 patients with solid renal masses (1.6 to 2.2 cm) per contrast-enhanced MRI or CT concerning for malignancy underwent single session CT-guided percutaneous cryoablation and subsequent biopsy of ablated tissue. Cryoablation was performed under CT and ultrasound guidance. An iceball margin of > 5 mm was confirmed prior to thawing and probe removal. Core biopsy was subsequently performed with an 18-gauge coaxial needle of the visible mass within the treated volume. Samples were submitted to pathology in formalin and underwent routine processing. All patients were subsequently followed in clinic with repeat imaging every 3 months. There were no post procedure adverse events related to biopsy. Median follow-up for the cohort was 154 days (IQR 191 days). All ablated lesions demonstrated complete response per MRI and CT (2-7 months). Histologic diagnostic quality was adequate for all submitted specimens yielding renal cell carcinoma or oncocytoma in 6 and 2 patients, respectively (Table 1). Diagnostic core biopsy of renal masses immediately post cryoablation is both safe and feasible. Potential benefits of this approach should be validated in future studies.Table 1Renal Cell Carcinoma TypeGradeClear cell2Clear cell3PapillaryLowClear cell papillaryLowChromophobeLowChromophobe- Open table in a new tab