AUA 2017: Renal Mass Biopsy is Associated with increased Incidence of Pathological Upstaging to Perinephric Fat Invasion in Patient with Clinically Localized Renal Cell Carcinoma.

Boston, MA (UroToday.com) The popularity of renal mass biopsy has been rising over the last 10 years following reports on increased accuracy and safety. Early on there was significant concern of tumor seeding following the biopsy but this risk has been mitigated with the use of coaxial approach. Dr. Salmasi, from UCLA, discusses the potential risk of perinephric fat invasion following renal mass biopsy caused by capsular disruption at the time of biopsy. In order to answer this question Dr. Salmasi queried the National Cancer Data Base (NCDB) to assess the likelihood of renal mass upgrading following renal mass biopsy and its association with overall survival.

The study included 47,294 patients of which 3,030 underwent renal mass biopsy prior to surgical excision. Covariates predictive of renal mass biopsy were increase age, decreasing renal mass, treatment at an academic institution, and contemporary diagnosis. When comparing the rate of upgrading between the two groups there was a significant increase associated with the renal mass biopsy group of 7.1 % vs. 5.9 %, p=0.012. If upgrading is stratified between perinephric fat invasion and sinus invasion, only the rate of perinephric fat invasion is noted to be increased in renal mass biopsy patients (4.1% vs. 3.2%, p=0.025). On multivariate regression analysis assessing the likelihood of perinephric fat invasion was associated with high grade (OR 1.93), increasing tumor size (OR 1.09) and receiving a renal mass biopsy (OR 1.26). On propensity matched survival analysis renal mass biopsy was associated with a significant decrease in overall survival.

The presenter concludes that renal mass biopsy is associated with upgrading of renal masses and should be performed with caution. The presenter makes a bold conclusion given the inherent limitations associated with large cancer registries such as the NCDB database. For instance, the data analyzed by the study lacks the patients who underwent biopsy but did not undergo surgery, which adds a great deal of selection bias into the analysis. In addition, there is lack of uniform pathological evaluation which may add bias the results. Finally, none of the large institutional renal biopsy series have shown increase risk of local progression and when patient’s progress is usually in a hematologic fashion.

Presented By: Amirali Salmasi M.D., UCLA Urology

Written By: Andres F. Correa, MD, Society of Urologic Oncology Fellow, Fox Chase Cancer Center, Philadelphia, PA

at the 2017 AUA Annual Meeting - May 12 - 16, 2017 – Boston, Massachusetts, USA

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