# Contemporary assessment of diagnostic performance and histologic concordance of renal mass biopsy with surgical pathology

## TL;DR

This study evaluates how accurate kidney mass biopsies are in diagnosing kidney cancer by comparing them with surgical results.

## Contribution

The study provides updated diagnostic performance metrics for renal mass biopsy in a large, contemporary cohort.

## Key findings

- RMB had 94% sensitivity and 98% positive predictive value for identifying RCC.
- High-grade RCC biopsies were confirmed at 100%, but 26% of low-grade RCC were upgraded at surgery.
- Sixty-six percent of oncocytic biopsy cases were confirmed as RCC at surgery.

## Abstract

Improvements in imaging and technique have led to a greater role for renal mass biopsy (RMB) to risk‐stratify localized renal masses. We sought to assess the contemporary diagnostic accuracy of RMB for identifying renal cell carcinoma (RCC) based on concordance with final surgical pathology.

Consecutive patients undergoing RMB between 2013 and 2023 across an 11‐hospital health system were identified. Concordance between RMB and final pathology for patients receiving partial or radical nephrectomy was compared. We calculated sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of RMB for identifying RCC among patients who underwent surgery.

A total of 733 patients underwent RMB with an overall non‐diagnostic rate of 11% and most biopsies (67%) identified RCC. A total of 243 patients with surgical pathology were analysed, and 229 (94%) had RCC on surgical pathology. Excluding non‐diagnostic cases, RMB had a 98% concordance with surgical pathology for RCC; RMB had 94% sensitivity, 71% specificity, 98% PPV and 42% NPV for identifying RCC with non‐diagnostic cases considered as benign biopsies. For the nine RMB oncocytic cases receiving surgery, six (66%) were RCC and only two (22%) were confirmed oncocytomas. For patients with biopsy grade reported, 100% of high‐grade RCC were confirmed while 26% of low‐grade RCC were upgraded at nephrectomy (overall 80% concordance).

In a large, contemporary cohort of patients, RMB had high PPV and sensitivity for identifying RCC and high concordance for specific histology at nephrectomy. However, upgrading was common, and oncocytic lesions selected for surgery due to clinical suspicion often harboured RCC.