The Problem of "Needless" Nephrectomy
Current guidelines do not mandate preoperative renal mass biopsy (RMB) for SRMs, which has led to an alarming rate of needless nephrectomies. Approximately 18% to 26% of nephrectomies are performed on benign tumors, posing unnecessary post-operative complications and long-term renal and cardiovascular risks to patients. This practice persists despite the availability of RMB, which offers high sensitivity and specificity comparable to other solid organ tumors such as breast, prostate, and lung which require mandatory biopsy before surgical treatment.
Renal Mass Biopsy in 2024
A review of literature confirms that RMB is as accurate—or more so—than other organ system biopsies where biopsy is regarded as standard care before surgery (breast, prostate, lung, pancreas, thyroid, and liver). With an impressive sensitivity and specificity, both at 98%, RMB exhibits almost flawless accuracy in diagnosing cancer. This reliability is underscored by a positive predictive value of 99.8, assuring that positive diagnoses genuinely represent the underlying condition. The negative predictive value of 69 and the inconclusive rate of 14% are attributable to the failed biopsy of normal renal tissue, which is minor given that inconclusive results substantially decrease to 2.8% after subsequent biopsy. To note, RMB has an exceptionally low complication rate (< 1%); a mere fraction of other mandatorily biopsied organs, such as the lung and prostate, which can have complication rates as high as 6% and 4%, respectively.
We advocate for a paradigm shift: surgery for SRMs should only be performed after RMB confirms malignancy. This approach would drastically reduce the rate of benign nephrectomies and support well-informed clinical decisions. Patients opting for active surveillance (AS) could benefit from RMB, enjoying a reduced psychological burden of living with an untreated mass and minimizing the risk of progression to metastatic disease.
Implementing Change
To implement this shift, we recommend routine RMB for all patients with non-fat-containing T1a SRMs who are candidates for surgery. For patients preferring AS, informed decision-making about RMB should be encouraged. For those with significant comorbidities or advanced age, RMB may not be necessary if treatment would not be pursued regardless of biopsy results.
In our series of 192 SRM patients at the University of California, Irvine, routine pre-treatment RMB significantly enhances outcomes. Among patients undergoing RMB, 37% avoid unnecessary surgery and instead enjoy low-risk active surveillance, with only 3% needing a subsequent procedure over an average of 6 years. Moreover, 38% undergo outpatient percutaneous ablation, with 89.5% requiring no further treatment and none experiencing disease progression. Best of all, the risk of "needless" nephrectomy plummets from 20-25% to a mere 3%.2
Conclusion
Our proposed shift towards routine RMB for SRMs aims to enhance patient outcomes by ensuring that surgical interventions are only undertaken when malignancy is confirmed. This strategy aligns with practices in other fields of oncology, where preoperative biopsies are standard care. Embracing RMB could significantly reduce the rate of needless nephrectomies, sparing patients from the risks and complications of surgery.
We hope this review stimulates discussion and re-evaluation of current guidelines, ultimately leading to improved management of SRMs and better patient care.
For a detailed discussion and analysis, please refer to our full article in Urologic Oncology: Seminars and Original Investigations.
Written by: Bruce Gao, Antonio R. H. Gorgen, Rohit Bhatt, Zachary E. Tano, Kalon L. Morgan, Kelvin Vo, Sina Soltanzadeh Zarandi, Sohrab N. Ali, Pengbo Jiang, Roshan M. Patel, Ralph V. Clayman, Jaime Landman
Department of Urology, University of California, Irvine, Orange, CA.
References:
- Gao B, Gorgen ARH, Bhatt R, Tano ZE, Morgan KL, Vo K, Zarandi SS, Ali SN, Jiang P, Patel RM, Clayman RV, Landman J. Avoiding "Needless" nephrectomy: What is the role of small renal mass biopsy in 2024? Urol Oncol. 2024 Apr 19:S1078-1439(24)00422-8. doi: 10.1016/j.urolonc.2024.04.002. Epub ahead of print. PMID: 38643022.
- Jiang P, Arada RB, Okhunov Z, Afyouni AS, Peta A, Brevik A, Xie L, Ayad M, Xu P, Morgan K, Tapiero S, Patel R, Nelson KJ, Lee JG, Clayman RV, Landman J. Multidisciplinary Approach and Outcomes of Pretreatment Small (cT1a) Renal Mass Biopsy: Single-Center Experience. J Endourol. 2022 May;36(5):703-711. doi: 10.1089/end.2021.0664. PMID: 35018788.
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