AUA 2019: Renal Mass Biopsy vs. Biopsy of Masses in Other Organs: Why Is It Different Only for the Kidney?

Chicago, IL ( Renal mass biopsy remains a controversial topic among urologists across the globe. Currently, among patients with small renal masses, a biopsy is not standard of care. Many urologists proceed to remove small renal masses despite literature revealing that up to 20% of these masses being benign. Among other solid organs such as prostate, lung, breast, and bladder, the standard of care mandates biopsy before any treatment.  Jefferson and colleagues sought out to compare both the efficacy and safety of renal mass biopsy of small renal masses. They compared their rates with the rates of other major organ systems.

The group reviewed meta-analyses, systematic reviews, and clinical studies with regards to biopsy of 6 organ systems, the prostate, lung, breast, thyroid, pancreas, and kidney. They only identified studies dealing with needle biopsy specifically.

Data regarding biopsy sensitivity, specificity, diagnostic accuracy, and complication rates were extracted from 10 total studies. The sensitivity and specificity of small renal mass biopsy were 99% and 98%, respectively. Among all other organ systems, sensitivity and specificity ranged from 48-99% and 96-100% respectively. Complication rates for renal mass biopsy was 8% and the diagnostic accuracy was 96%. Jefferson stated that these rates were comparable to biopsy results of the other organs. Alarmingly, the complication rate for lung biopsy was as high as 21%.

Knowing the 20% incidence of benign diagnosis of small renal masses at the time of removal, a 7% pre-treatment biopsy rate of renal masses versus 100% biopsy rate for other organs, seems shocking. This group from the University of California, Irvine, advocate for routine preoperative needle biopsy for small renal masses to save 20% of kidneys from being unnecessarily operated on.

Presented and written by: John Sung, Department of Urology, University of California-Irvine, @JohnM_Sung at American Urological Association's 2019 Annual Meeting (AUA 2019), May 3 – 6, 2019 in Chicago, Illinois