A systematic review of renal mass biopsy: what evidence supports its use (or omission)?

Aim: Management of clinically localized renal masses ≤ 7 cm (cT1RM) is typically guided by imaging rather than renal mass biopsy (RMB), unlike most other malignancies, where tissue diagnosis precedes treatment decisions. Despite advancements, fewer than 25% of cT1RM patients undergo RMB before surgery or active surveillance (AS). While imaging modalities such as CT, magnetic resonance imaging (MRI), and ultrasound can often identify benign lesions (e.g., Bosniak I-IIF cysts, angiomyolipoma), decisions regarding solid, enhancing masses and Bosniak III-IV cysts frequently proceed without histological confirmation of renal cell carcinoma. This practice may lead to potentially unnecessary or “needless” interventions. AS has emerged as a viable alternative to surgery for renal masses < 3-4 cm, showing low metastatic progression rates comparable to those seen with intervention. Methods: We systematically reviewed observational studies (retrospective and prospective) due to the absence of randomized controlled trials on RMB for cT1RM. Results: Reported sensitivity, specificity, positive predictive value, and negative predictive value of RMB range from 93%-99%, 71%-100%, 97%-100%, and 38%-63%, respectively. Safety data affirm RMB as a low-risk procedure, with minor complications (e.g., bleeding, hematoma) occurring in < 5% of cases and hospital admissions/readmissions in < 3%. Conclusion: While RMB is accurate, its role in treatment planning remains underexplored. Emerging evidence suggests increased adoption of non-interventional approaches (e.g., AS), with RMB influencing treatment decisions (e.g., avoidance of nephrectomy) in 10%-30% of cases. Future studies should investigate when RMB is warranted, its influence on treatment selection, and its effects on patient-centered outcomes such as decisional conflict and regret.