AUA 2019: Tumor Seeding in the Tract of Percutaneous Renal Tumor Biopsy. A Report of Seven Cases From A UK Tertiary Referral Centre
Historically, the treatment for patients with small renal masses was surgical excision with partial or radical nephrectomy. A recent approach has been to perform a percutaneous renal mass biopsy (RMB) to establish a histologic diagnosis prior to definitive surgery. Currently, such an approach is controversial3,4 as the ability to acquire valuable diagnostic information that can risk stratify patients5 must be weighed against a non-diagnostic rate of approximately 15% and the risk of procedure-related complications 6,7. One of the most worrisome outcomes of renal mass biopsy is tumor seeding. Currently, guidelines suggest this to be an extraordinarily uncommon event. In a podium presentation at the American Urologic Association Annual Meeting, Dr. Sullivan and colleagues present the results of careful histopathologic examination of the tumor tract among patients undergoing resection following renal mass biopsy.
The authors identified 585 renal tumor resections and 196 renal tumor biopsies that were performed at their tertiary care institution between January 2014 and September 2017. Following resection, the renal tumor biopsy tract was carefully examined in each specimen to identify abnormalities. Where macroscopic abnormalities were present, a further microscopic assessment was performed.
The authors identified seven cases (3.6%) of renal tumor biopsy tract seeding, among 196 renal tumor biopsies performed. Pathological analysis found the underlying histology to be papillary RCC in six of seven cases, and clear cell RCC in the remaining. In six of the seven cases, renal tumor biopsy tract seeding resulted in the presence of tumor in the perinephric fat which therefore resulted in tumor upstaging to pT3a in tumors which would otherwise have been classified pT1. Two of the seven patients subsequently develop local tumor recurrence within the renal bed at anatomic sites which are consistent with the biopsy tract location.
This series represents the largest assessment to date of histologically-proven renal tumor biopsy tract seeding, equally the remainder of the published literature to date. While renal tumor biopsy can provide valuable information to guide patient treatment decision making, the risk of tumor seeding within the tract is a real, although small, risk that should be discussed. Such seeding results in tumor upstaging although, given the small numbers to date, the prognostic significance of this is unclear. At a minimum, patients are likely to receive significantly more post-operative surveillance imaging than they otherwise would have.
Presented by: Mark Sullivan, MBBS, MD, FRCS, Churchill Hospital, Oxford, United Kingdom
Written by: Christopher J.D. Wallis, Urology Resident, University of Toronto, @WallisCJD at American Urological Association's 2019 Annual Meeting (AUA 2019), May 3 – 6, 2019 in Chicago, Illinois
References:
1. Gill IS, Aron M, Gervais DA, Jewett MA. Clinical practice. Small renal mass. The New England journal of medicine 2010; 362(7): 624-34.
2. Frank I, Blute ML, Cheville JC, Lohse CM, Weaver AL, Zincke H. Solid renal tumors: an analysis of pathological features related to tumor size. The Journal of urology 2003; 170(6 Pt 1): 2217-20.
3. Patel HD, Johnson MH, Pierorazio PM, et al. Diagnostic Accuracy and Risks of Biopsy in the Diagnosis of a Renal Mass Suspicious for Localized Renal Cell Carcinoma: Systematic Review of the Literature. The Journal of Urology 2016; 195(5): 1340-7.
4. Campbell S, Uzzo RG, Allaf ME, et al. Renal Mass and Localized Renal Cancer: AUA Guideline. The Journal of Urology 2017.
5. Richard PO, Jewett MAS, Bhatt JR, et al. Renal Tumor Biopsy for Small Renal Masses: A Single-center 13-year Experience. European Urology 2015; 68(6): 1007-13.
6. Leveridge MJ, Finelli A, Kachura JR, et al. Outcomes of small renal mass needle core biopsy, nondiagnostic percutaneous biopsy, and the role of repeat biopsy. European urology 2011; 60(3): 578-84.
7. Prince J, Bultman E, Hinshaw L, et al. Patient and Tumor Characteristics can Predict Nondiagnostic Renal Mass Biopsy Findings. The Journal of Urology 2015; 193(6): 1899-904.