ASCO GU 2017: Contemporary Role of Percutaneous Biopsy for the Small Renal Mass - Session Highlights
Orlando, Florida USA (UroToday.com) Dr. Alessandro Volpe reported that renal mass biopsy (RMB) is still controversial for the diagnosis of small renal masses (SRMs), with the reasons being doubts regarding its safety, technique, and efficacy. However, he noted that RMB requires only local anesthesia, uses ultrasonographic guidance, is an outpatient procedure, and leads to only minimal pain. The risk of tumor seeding is exceedingly rare, and bleeding occurs in 0% to 1.3% of cases, with the literature indicating that tThe diagnostic yield of RMB ranges between 79% and 100%. In cases of nondiagnostic biopsy, most guidelines recommend a repeat biopsy. Indeed, the assessment of accuracy is limited due to the retrospective nature of most studies, the different techniques used, and the lack of ideal pathologic reference in many cases. Core biopsy has been found to be more accurate than fine-needle aspiration, with sensitivity and specificity of 99.1% and 99.7%, respectively, for diagnosing malignancy. Furthermore, the accuracy of RMB for diagnosing histotypes is 90.3%. On the other hand, diagnosing nuclear grade is more difficult, with accuracies of 62.5% and 87%, respectively, for 4- and 2-tier grading systems.
Dr. Volpe indicated that RMB can help in clinical decision making in several situations. The finding of a benign tumor or a low malignant-potential tumor on RMB may obviate the need for surgery in the patient with a high surgical risk. In addition, when there is concern for metastatic renal cell carcinoma, but cytoreductive nephrectomy is not planned, RMB can provide tissue diagnosis prior to systemic therapy. The same reasoning may be applied to RMB before planned ablative treatment.
Some tumor features lead to lower diagnostic yield and a higher risk of complications, which include cystic tumors, tumors smaller than 15 mm, and tumors in difficult locations (eg anterior or perihilar). A number of patient characteristics also render RMB unhelpful, such as the patient being young or the person’s comorbidities. In these cases, the biopsy result will not change the clinical management since the young patient will undergo resection and the comorbid patient will be put on active surveillance regardless of the RMB result.
Presenter: Alessandro Volpe, MD university of south piedmont, Italy
Written By: Miki Haifler, MD, M.Sc, Fox Chase Cancer Center