Cystic features, contrast enhancement predict risk of nondiagnostic findings in renal mass biopsy
A recent study has shown that procedural complications following percutaneous core renal mass biopsy are uncommon even with low serum platelets, a mildly increased international normalized ratio (INR) or when patients are on aspirin.
Additionally, the risk of nondiagnostic findings is independently predicted by cystic features, hypo-enhancement on imaging, a smaller mass diameter and a longer skin-to-tumour distance.
A total of 1,155 biopsies were performed in 965 patients, of whom 24 (2.2 percent) had procedural complications, including five (0.4 percent) with major complications (Clavien ≥3a). None of the patients had tumour seeding of the biopsy tract.
The following factors did not correlate with the risk of complication (p=0.06–0.53): age, gender, body mass index, Charlson comorbidity index, smoking, mass diameter, nephrometry score, number of cores and prior biopsy.
Complications were not elevated for patients taking aspirin (p=0.16) or those with low platelets (25,000–160,000/μl blood; p=0.07) or a mildly increased INR (1.2–2.0; p=0.50). No increase in complication risk was seen during the initial 50 cases of a radiologist (p=0.35) or when a trainee was present (p=0.12).
Of the biopsies, 14.6 percent presented with nondiagnostic findings, which were independently associated with cystic features (p<0.001), contrast enhancement (p=0.002), mass diameter (p=0.02) and skin-to-mass distance (p=0.049), but not with radiologist experience (p=0.23). Previous nondiagnostic biopsy did not correlate with an elevated nondiagnostic rate on subsequent attempts (19.2 percent vs 14.2 percent; p=0.23).
In this study, the authors reviewed core renal mass biopsies from 2000 to 2017 and used the Clavien-Dindo system to grade complications at ≤30 days. They also performed univariate and multivariate analyses to examine associations between clinical characteristics and the risk of complications or nondiagnostic findings.