AUA 2018: Complications following 1053 Percutaneous Core Renal Mass Biopsies: Risk Factors and Safety Assessment

San Francisco, CA ( Percutaneous renal mass biopsy (RMB) is an effective diagnostic tool. Although morbidity of RMB is generally minimal, few studies have investigated risk factors and safety, and complications. The purpose of this project was to evaluate patient, tumor, and technical factors associated with procedural complications following RMB.  Consecutive patients treated with percutaneous core RMB from 2003-2017 were included in this analysis. According to the trial protocol, RMB was performed with an INR up to 2.0, platelets > 25,000 and continuation of aspirin (ASA) therapy. Complications within 30 days were graded using the Clavien-Dindo classification system.

Logistic regression analysis evaluated associations between complications and: age, gender, body mass index (BMI), Charlson Comorbidity Index (CCI), smoking status, pre-procedure labs (platelets, INR, hemoglobin), ASA, blood pressure during procedure, tumor diameter, Nephrometry score, biopsy needle size, US vs. CT guidance, number of needle passes, presence of trainees, and the radiologist’s prior experience.  

Of 1155 patients undergoing biopsy (Figure 1), 24 (2.2%) patients had procedural complications including: symptomatic hematomas 6 (0.6%), gross hematuria 8 (0.8%), severe pain 4 (0.4%), UTI 4 (0.4%) and one patient each with hypotension, pseudoaneurysm and urinary retention. Major complications (Clavien 3a) were identified in 5 (0.5%) patients and 11 (1.0%) were admitted to the hospital. No patients had tumor seeding from the biopsy. Age, BMI, gender, CCI, smoking status, platelet count, INR, hemoglobin, and blood pressure were not associated with complications (p=0.48, 0.09, 0.10, 0.33, 0.47, 0.16, 0.41, 0.46, 0.30). No associations were identified with complications and tumor diameter, Nephrometry score, needle size, type of radiologic guidance, or number of needle passes (p=0.30, 0.18, 1.0, 0.27, 0.10). RMB was performed in 401 (38%) patients on Aspirin and 51 (4.8%) with INR > upper limit normal. Risk was not increased in patients on aspirin or for patients with INR 1.3-2.0, p=0.23 and 0.41, respectively. Trainee presence did not increase complication rate, p=0.24. Twelve radiologists performed at least 50 RMB, median 83 (range 54-136) (Figure 2). Complications rates ranged from 0-2.3%, but no difference was identified between the most and least experienced radiologists, p=0.21. Risk was not increased during radiologist’s first 50 cases, p=0.23.  

Lastly, factors associated with a non-diagnostic result included cystic lesions, non-enhancing lesions on MRI, increased skin to tumor distance, and smaller diameter of the renal mass. In contrast, radiologist experience was not associated with a higher non-diagnostic rate (Figure 2). 

In summary, renal mass biopsy is safe for patients with platelets > 25,000 or INR 1.3-2.0 and Aspirin did not increase complication risk. Furthermore, the number of needle passes, BMI, co-morbidities and radiologist experience were also not associated with complications. 

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Figure 1: Rena mass biopsies performed by year: 

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Figure 2 – Complications and Multivariable logistic regression analysis assessing factors associated with non-diagnostic rate: 

Presented By: Natasza Posielski, Madison, WI, US 

Written by: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre Twitter: @GoldbergHanan at the 2018 AUA Annual Meeting - May 18 - 21, 2018 – San Francisco, CA USA
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