SMALL RENAL MASSES IN 100 PATIENTS: HOW MANY TUMOURS ARE DETECTED WITH IMAGING-GUIDED RENAL BIOPSY
As the use of radiological investigations has increased in the last years, the detection of small renal masses (SRMs) < 4 cm has become more frequent. In most cases the radiological distinction between benign and malignant SRMs cannot be performed. According to the results of recent studies the use of US-guided percutaneous renal biopsy (RTB) or Computerised Tomography (CT)-guided RTB is diagnostic and accurate with low complication rates.
Materials and Methods
We performed a retrospective analysis of our experience with US/CT-guided RTBs of SRMs suspicious for renal cancer from 2010 to 2015. We collected and analysed our data about size, site, histopathology,Fuhrman grade, type of radiological imaging used to perform a biopsy, peri-operative complications (according to Clavien-Dindo classification ), surgical treatment of tumours and number of RTBs required to get a correct diagnosis. Patients whose first RTB was non-diagnostic of renal cell carcinoma were followed up and they got a second biopsy if required.
100 patients were enrolled with an average age of 71. SRMs were detected by means of US-guided biopsies and CT-guided biopsies in 19% and 81% of cases respectively. Local anaesthesia was performed in 97% of cases. The lesions were located in the right, left or in both kidneys in 46%, 52% and 2% of cases respectively. Post-operative complications occurred in 3% of cases ( Clavien Dindo 1 and 2 ) and all were treated conservately. 66% of the lesions proved to be malignant. Fuhrman grade was assigned by experienced genitourinary pathologist in all renal cell carcinomas and was used to stratify cases into low- and high risk; Fuhrman grade 1-2 or 2-3 were considered to be low-risk renal tumors (n=25) and Fuhrman grade 3 and 4 were classified as high risk (n=5). In the 54% of cases physicians had performed a US-guided RTB, in the 12% a CT-guided RTB. 6% of RTBs were non-diagnostic because they contained insufficient material for the analyses (3% necrotic tissue and/or blood 2%, 1% inflammation/fibrosis), 9% revealed benign lesions and 6% were over diagnoses. 77% (n=51) of patients whose RTBs detected the presence of cancer were treated in our clinical centre: 29% were treated with partial nephrectomy, 48% with tumorectomy. A strong link (86% rate) was high lighted between the histological findings in the biopsy and the post-operative ones. We followed up patients with a first non-diagnostic RTB: 21% were diagnostic after a second RTB, 2% were non-diagnostic and 11% were diagnostic after a third biopsy.
The use of CT and US-guided biopsy is a safe and accurate method to discriminate between benign and malignant lesions. Its limits reside in the amount of removed tissue. Our study was aimed to assess its efficacy and to find out how many biopsies are required in order to make a correct diagnosis. Thus US or CT-guided renal biopsies are a valid method of investigating suspicious renal lesions (<4 cm) thanks to their high reliability and a low complication rate.
The US and TC-guided biopsy is a safe method with 3% rate of complications and has an accuracy of 86% for SRMs diagnosis at the first biopsy and 14% at the second biopsy.Argomenti: cancro del rene