Under‐grading of <4 cm renal masses on renal biopsy

Abstract

Study Type – Prognosis (case series) Level of Evidence 4 What's known on the subject? and What does the study add? It is well documented that biopsy of small renal masses is inaccurate and tends to under‐estimate tumour grade compared with surgical specimens. To our knowledge there has not been a study showing grading discrepancy between biopsy and surgical excision in a large population‐based cohort. OBJECTIVE To determine whether differences exist in tumour grade between patients who undergo partial nephrectomy (PN) and those who undergo ablation for renal tumours. PATIENTS AND METHODS Data was obtained using the Surveillance, Epidemiology and End Results database. Patients with solitary renal tumours of <4 cm treated with ablation or PN and with renal cell carcinoma (RCC) histopathology were identified. Tissue diagnosis in the ablation specimens was obtained from biopsy reports, whereas tissue from PN specimens was determined from surgical pathology. Variables analysed included: year of diagnosis, age, sex, race/ethnicity, marital status, population density, education, poverty level, and tumour size. Stacked bar graphs were created to compare the distributions of grade and histology between the groups. Multinomial logistic regression was used to determine factors independently associated with grade. RESULTS In all, 7704 (87.4%) patients underwent PN and 1114 (12.6%) underwent either radiofrequency ablation or cryoablation. The PN patients were younger at diagnosis (59 vs 68 years, P < 0.001), more likely to be married (70% vs 64%, P < 0.001), and had smaller tumours (2.4 vs 2.6 cm, P < 0.001). There were no differences in the distribution of histology between the PN and ablation groups. Tumour grade was significantly lower in tumours treated with ablation. Compared with grade 1 disease, those undergoing ablation were 30% less likely to have grade 2 (P < 0.001), 30% less likely to have grade 3 (P < 0.001), and 92% less likely to have grade 4 disease (P < 0.01) than those having PN. CONCLUSIONS There is a strong association between grade and treatment type in patients with small renal masses after controlling for baseline characteristics. As grade is determined by different methods, we think that this shows systematic under‐grading in biopsy of small renal masses.

Utility of fine‐needle aspiration and core biopsy with touch preparation in the diagnosis of renal lesions

“…A recent large series of 405 biopsies showed concordant Fuhrman nuclear grades in preoperative biopsies and nephrectomy specimens in only 38.3% . Most contemporary reviews and series conclude that Fuhrman nuclear grading has lower accuracy in renal biopsies …”

“…Most discrepancies in nuclear grade are within one grade and are most likely due to tumor heterogeneity . Millet et al reported an improved concordance in nuclear grading using a 2‐tiered simplified Fuhrman classification (Fuhrman I‐II = low grade; Fuhrman III‐IV = high grade) over a 4‐tiered Fuhrman classification .…”

“…11,13,[15][16][17][18][19] Most discrepancies in nuclear grade are within one grade and are most likely due to tumor heterogeneity. 11,[15][16][17][18][19] Millet et al reported an improved concordance in nuclear grading using a 2-tiered simplified Fuhrman classification (Fuhrman I-II 5 low grade; Fuhrman III-IV 5 high grade) over a 4-tiered Fuhrman classification. 17 Our series has only 3 cases which were graded by both biopsy and nephrectomy, with moderate agreement (67%).…”

Small renal mass biopsy – how, what and when: report from an international consensus panel

“…These phenomena may have accounted for the findings of Harris et al. suggesting under‐grading of RCC on biopsy compared with final pathology.…”

Termoablación con radiofrecuencia de tumores del parenquima renal

“…El flujo constante de sangre a temperatura corporal condiciona un enfriamiento de partes del tumor adyacentes a los vasos sanguíneos. Debido a estos limites para alcanzar picos de temperatura y de duración adecuada es por lo que los resultados en cuanto a ablación completa de este tipo de tumores son inferiores y en gran medida precisan la aplicación de un número mayor de sesiones de RF(Beland et al 2011),(Karam et al 2011),(Okhunov et al 2012),(Park et al 2010),(Patel et al 2013),(Prevoo et al 2010),(Velasco et al n.d.),(Zhang et al 2012),(Zurera et al n.d.).Siguiendo las indicaciones de la Asociación Europea de Urología (EAU), la biopsia renal debe realizarse en los siguientes supuestos(Aribaş et al 2011),(Fotiadis & Matson 2009),(Harris et al 2012),(Klingler & Susani 2010),(Kyle et al 2008), (Ortiz-Alvarado & Anderson 2010),(Pandharipande et al 2010),(Remzi & Marberger 2009),(Tan et al 2012):…”