Renal mass sampling: An enlightened perspective

Abstract

Renal mass sampling (RMS) can be carried out by core biopsy or fine needle aspiration with each presenting potential advantages and limitations. The literature about RMS is confounded by a lack of standardized techniques, ambiguous terminology, imprecise definitions of accuracy, substantial rates of non-informative biopsies, and recurrent diagnostic challenges with respect to eosinophilic neoplasms. Despite these concerns, RMS has an expanding role in the evaluation and treatment of renal masses, in order to stratify biological aggressiveness and guide management that can range from surgery to active surveillance. Non-informative biopsies can be managed with surgical excision or repeat biopsy, with the latter showing encouraging results in recent studies. We propose a new classification in which all biopsies are categorized as non-informative versus informative, with the latter being subclassified as confirmed accurate, presumed accurate or confirmed inaccurate. This terminology will facilitate the comparison of results from various studies and stimulate progress. Incorporation of novel biomarkers and molecular fingerprinting into RMS protocols will likely allow for more rational management of patients with renal masses in the near future.

Diagnostic Accuracy and Risks of Biopsy in the Diagnosis of a Renal Mass Suspicious for Localized Renal Cell Carcinoma: Systematic Review of the Literature

“…We found repeat biopsy can potentially lead to diagnosis in 80% of patients with initially nondiagnostic results. The nondiagnostic rate was similar to the previously reported range of 10% to 20%, 6 but the rate of malignancy at extirpation among nondiagnostic biopsies has not been previously reported to our knowledge. Also, relative to prior reviews of the literature, we excluded series with large renal masses that were not stated to be localized, as well as biopsy studies before ablation procedures.…”

“…The limitation of the literature has been previously acknowledged but addressed for the first time in the current systematic review by cross tabulating raw data from individual studies. 6 For the clinically relevant scenario of a patient with a renal mass biopsy result, a positive biopsy was associated with a high PPV compared to the gold standard, indicating strong confidence in a positive result. On the other hand, a negative biopsy result led to greater uncertainty with 36.7% of those undergoing extirpation found to have malignant disease.…”

“…1 Increasing incidental detection has led to the diagnosis of more asymptomatic, small and clinically localized renal masses, approximately 20% of which are benign at surgical resection. [2][3][4][5][6] It is estimated that 6,000 benign renal masses are removed each year. 7 Renal mass biopsy provides a potential route for tissue sampling to aid in histological and subtype diagnosis for risk stratification and management.…”

Active surveillance for clinically localized renal tumors: An updated review of current indications and clinical outcomes

“…33 Even though the diagnostic accuracy is progressively improving, according to the current recommendations not all patients with SRM are ideal candidates to RTB, but only those patients in which a percutaneous biopsy is going to impact the future clinical management. 14,35 In these different scenarios, RTB could reduce the morbidity of unnecessary procedures and, in contrast, maximize treatment effectiveness. To date, the currently available series underline the feasibility and safety of active surveillance for cT1a RCC, but very little is known about the natural history of such tumors that have remained on AS for a long period.…”

“…[38][39][40] In a comprehensive meta-analysis of 10 studies from nine single-institutional series, Chawla et al reported outcomes of 234 expectantly managed SRM. 11 The evaluated series included six to 40 patients, with a mean follow up of 34 months (median 32, range [26][27][28][29][30][31][32][33][34][35][36][37][38][39]. In all series combined together, the mean tumor size at presentation was 2.6 cm (median 2.48 cm), and the mean linear growth rate was 0.28 cm/year.…”