The Trend of Application of Renal Mass Biopsy for Clinical Management of Patients with Renal Mass Lesions

Summary: Introduction: Renal mass biopsy (RMB) has increasingly become a part of the clinical management of patients with renal mass lesions as suggested by the guidelines of urologic societies of both the United States and Europe. Despite its growing inclusion in clinical guidelines, the utility and practical application of RMB continue to be subjects of ongoing debate. Moreover, there is a lock of comprehensive data on the trends and outcomes associated with over extended periods. Materials and Methods: A retrospective review was conducted on RMB cases spanning from July 2002 to April 2023. The diagnoses of RMB cases were classified into six categories: non-diagnostic, benign neoplasms and non-neoplastic lesions, low-grade (LG) oncocytic neoplasm (LG chromophobe renal cell carcinoma versus benign oncocytic tumors), atypical, suspicious for malignancy, and malignant. Results: 899 cases were retrieved, 24 fine needle aspirate (FNA), 131 combined FNA and core needle biopsy (CNB), and 744 CNB cases (Figure 1). There was a noticeable trend in the application of RMB, with a gradual increase observed from 2002 to 2018, and a sharp rise post-2019. The usage of RMB modalities shifted from predominantly FNA or FNA/NCB between 2002 and 2008 to predominantly CNB from 2013 onwards. The non-diagnostic rate of RMB was relatively low (9%) (Table 1). The Risk of malignancy (ROM) was lowest in the benign category (7%), while it reached 100% in the malignant category, bringing the overall ROM of RMB to 69%. The ROM significantly influenced patient management, with higher ROM prompting more aggressive interventions such as nephrectomy and/or systemic treatments (chemo-radiation, targeted therapy), Conversely, less aggressive approaches like surveillance were preferred for low ROM benign lesions. Ablation techniques were typically reserved for benign, LG, or smaller neoplasms. Conclusions: RMB has increasingly become an essential diagnostic tool in the pretreatment evaluation of renal masses, significantly influencing the therapeutic direction based on the ROM associated with various diagnostic categories. The data affirm that ROMB's low non-diagnostic rate and its pivotal role in clinical decision-making underscore the necessity for biopsy in cases of ambiguous renal basses prior to determining the course of management.