# Computed tomography–guided percutaneous biopsy in diagnosis of suspected metastatic renal cell carcinoma: which location is the most suitable?

## TL;DR

This study examines the best biopsy location for diagnosing metastatic kidney cancer, finding that biopsies outside the kidney have fewer complications without affecting diagnostic accuracy.

## Contribution

The study identifies that non-renal biopsy locations offer lower complication rates without compromising diagnostic accuracy in metastatic renal cell carcinoma.

## Key findings

- Biopsies outside the kidney had a lower complication rate compared to kidney biopsies.
- There was no significant difference in diagnostic accuracy between kidney and non-kidney biopsy locations.
- Most biopsy results were true-positive, with a small percentage requiring rebiopsy due to false-negative results.

## Abstract

Systemic targeted therapy options are commonly used in patients with metastatic renal cell carcinoma (mRCC). Histological verification is crucial for treatment of mRCC.

Our aim was to evaluate an optimal location for percutaneous computed tomography‑guided biopsy in a diagnosis of suspected mRCC.

A total of 138 percutaneous biopsies for tumors ranging from 21 to 133 mm in diameter (median, 72 mm) were carried out in 134 patients with suspected mRCC over a 5‑year period. The biopsy location was variable, with kidney biopsy performed in 77 cases (55.8%), and other localizations (retroperitoneum, peritoneal cavity, liver, pelvis, pleural space, lung, mediastinum, chest or abdominal wall, and pancreas) in 61 cases (44.2%).

As many as 288 biopsies (97.1%), yielded truepositive results, and 4 procedures (2.9%) yielded histologically falsenegative results that required confirmation through extended rebiopsy. RCC was the most common individual diagnosis (85.5%), with non‑RCC histology verified in 14.5% of cases. In total, 32 complications (23.2%) were confirmed, 2 of which were pneumothoraces, 29 were minor bleeding that needed only conservative management, and 1 case required angiography and embolization for hemorrhage treatment. While no significant relationship between the biopsy success and lesion localization (renal vs other) was found (P = 0.13), the relationship between complication rate and biopsy localization (renal vs other) was significant (P = 0.01).

Lesion localization (renal vs other) was not relevant to histological accuracy of the biop‑ sies performed in patients with suspected mRCC. However, the biopsies of lesions outside the kidney had a lower complication rate.