EAU 2019: Patterns of Renal Mass Biopsy Across the MUSIC-KIDNEY Statewide QI Collaborative

Barcelona, Spain (UroToday.com) In recent years, the role of renal mass biopsy (RMB) has significantly increased in the management of small renal tumors. However, the safety issues and suboptimal diagnostic accuracy in case of fine-needle aspiration biopsy have led to varied utilization across the United States. The Michigan Urological Surgery Improvement Collaborative: Kidney mass: Identifying and Defining Necessary Evaluation and therapY (MUSIC-KIDNEY) program is a QI initiative for patients with renal masses ≤7 cm (RM≤7cm). In the pilot study presented by Amit Patel from Vattikuti Urology Institute an assessment of the use of RMB for newly-diagnosed RM ≤ 7cm across a range of practices types was performed.

MUSIC-KIDNEY commenced data collection in September 2017 at 8 diverse MUSIC practices. Data was collected for 581 patients with RM≤7cm, of which only 71 (12.2%) underwent a RMB. A frequency of RMB across the 8 sites ranged from 0-23% (median 11%), with 11% of RMB performed by a urologist (fig. 1). There was no statistical difference in patient and tumor characteristics between those having or not having RMB. In 2 cases out of 71, an emergency admission was required (with 1 hospitalization). The non-diagnostic rate of RMB across the collaborative was only 5.6% (n=4); the remaining RMB were categorized as benign (n=16, 22.5%), favor malignancy (n=4, 5.6%), or malignant (n=47, 66.2%). Active surveillance was suggested more often to the patients with a benign biopsy in comparison with patients without RMB (81% vs 48%, p=0.009). In addition, 15 patients (25%) with malignancy at RMB chose surveillance. The benign histology rate at surgery in RMB naïve patients was 13.1% vs 3.03% with RMB (p=0.09).

Figure 1: Use of RMB per tumor size
EAU 2019_ renalmassbiopsy_1.png

Authors concluded that this pilot study showed significant variability in the utilization of RMB and a favorable non-diagnostic rate compared to the literature. Only 3% of patients in the RMB cohort had benign histology at surgical intervention as compared to 13% with no prior biopsy. No patient with a benign result of RMB underwent radical nephrectomy. As was pointed out during the discussion, benign pathology rate in the literature is about 15-20%, but in some studies, this value reached up to 30%. Also, prof. Patel A. mentioned that even in case of RM > 7 cm, RMB can still have a diagnostic role, e.g. in differentiating metastases and primary tumor.

EAU 2019_ renalmassbiopsy .png

Presented by: Amit Patel, MD, Department of Urology, Henry Ford Health System, Vattikuti Urology Institute, Detroit, Michigan, United States

Written by:  Kirill Shiranov, MD, Fellow, Department of Urology, Rostov University, Rostov on Don, Russia, Twitter:  @endourologist and Zhamshid Okhunov, MD, Twitter: @OkhunovZham, Department of Urology, University of California-Irvine at the 34th European Association of Urology (EAU 2019) #EAU19, conference in Barcelona, Spain from March 15-19, 2019.