title: Percutaneous Renal Biopsies for Small Renal Masses: Complex Tumors on Nephrometry Should Be the First Targets.
abstract: To assess the diagnostic yield, accuracy, and complications rate for computed tomography (CT)-guided renal biopsies for solid renal masses (SRM); to analyze predictive factors for diagnostic biopsies.
  
  
  
  We performed a single-center, retrospective study based on a pathologic database query for CT-guided, percutaneous renal biopsies. Inclusion criteria included presence of SRM; exclusion criteria included the presence of metastases, non-cT1a or higher cancer (> 4 cm), and non-CT-guided techniques. Of 119 patients who underwent renal biopsies, 40 (34%) were excluded from the study; 79 (66%) biopsy outcomes were analyzed. Clinical, radiologic (RENAL score), and pathologic features were reported. Differences between contributive and noncontributive biopsies were tested with Mann-Whitney U or chi-square tests, as appropriate. Multiple-variable analyses searching for predicting factors of biopsy contribution were performed with binary logistic regressions.
  
  
  
  CT-guided renal biopsies for SRM present a high yield (88.6%) and high accuracy for differentiating malignant from benign tumors (96%). They are less accurate for histologic subtype (93%) and unreliable for Fuhrman grading (64%). CT-guided renal biopsy is safe (minor complication rate, 2.5%) and helped prevent unnecessary surgery in 30.4% of the cohort. Tumor complexity with high RENAL score was a predictive factor (P = .02) of contributive biopsy.
  
  
  
  SRM biopsy is a safe, reliable procedure that can help determine the best treatment strategy for patients. It seems more beneficial for nephrometry complex tumors when surgical extirpation is more likely to be complicated. SRM biopsy might be encouraged in clinical practice for complex tumors.
authors.affiliation: Urology Department, Institut Montsouris, Paris, France; IR4M, CNRS, Univ. Paris Sud, Université Paris-Saclay, Villejuif, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Ingels
authors.affiliation: Urology Department, Institut Montsouris, Paris, France. Electronic address: eric.barret@imm.fr.
authors.forename: Eric
authors.initials: E
authors.lastname: Barret
authors.affiliation: Urology Department, Institut Montsouris, Paris, France.
authors.forename: Rafael
authors.initials: R
authors.lastname: Sanchez-Salas
authors.affiliation: Urology Department, Institut Montsouris, Paris, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Galiano
authors.affiliation: Urology Department, Institut Montsouris, Paris, France.
authors.forename: François
authors.initials: F
authors.lastname: Rozet
authors.affiliation: Pathology Department, Institut Montsouris, Paris, France.
authors.forename: Stephane
authors.initials: S
authors.lastname: Lenoir
authors.affiliation: Radiology Department, Institut Montsouris, Paris, France.
authors.forename: Nina
authors.initials: N
authors.lastname: Weber
authors.affiliation: Urology Department, Institut Montsouris, Paris, France.
authors.forename: François
authors.initials: F
authors.lastname: Audenet
authors.affiliation: Urology Department, Institut Montsouris, Paris, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Cathelineau
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D061705:Image-Guided Biopsy / Q000379:methods*; D007680:Kidney Neoplasms / Q000175:diagnosis*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: Biopsy; Computed tomography; Diagnostic yield; RENAL nephrometry score; Renal-cell carcinoma