Smaller renal masses (less than 4 cm) are often benign, and most tumors that we ablate are less than 4 cm.
Patients undergoing partial nephrectomy, which involves smaller tumors, approximately 30% of patients have benign tumors.
This suggests that 30% of patients are being taken to the operating room for benign tumors.
Any small tumor should undergo biopsy, because the prevalence of benign tumors is so high.
Biopsy is helpful guide management and should be done prior to or at the same time as thermal ablation.
Biopsy is not necessary in unhealthy patients or in healthy patients in whom management will be surveillance only.
Biopsy should be done when biopsy will change clinical management.
Biopsy does not spread the tumor.
Diagnostic accuracy approaches 90% to 95%.
Complications or risks that occur with biopsy include: bleeding although the risk after biopsy is very low, particularly with image-guided biopsy, a non-diagnostic biopsy, around 5% to 15%.
Fiindings of a renal mass on imaging studies containing fat are diagnostic of an angiolipoma and do not need a biopsy.
Imaging should not be used to make a differentiation between different types of cancer.
Biopsy is important for patients with bigger tumors for which ablation is not an option.
Guidelines support the role of biopsy in the management of small renal masses.
Ideally performing ablations and biopsies at the same time, or staging the intervention with a biopsy first, followed by an ablation.