Renal tumor biopsy (RTB) for the characterization of small renal masses (SRMs) is safe and reliable and avoids unnecessary treatment, according to a new study.

A team led by Antonio Finelli, MD, of the University of Toronto, retrospectively studied 509 patients who underwent 529 biopsies for solid SRMs 4 cm or less in diameter. RTBs yielded an overall diagnostic rate of 94%. Following RTB, treatment could have been avoided in at least 26% of cases because the lesion was benign, the researchers reported online ahead of print in European Urology.

“Routine RTB should be considered in all patients with an indeterminate SRM for which treatment is being considered,” the investigators concluded.

Study results showed that 175 patients underwent surgery following RTB. Surgical pathology was unavailable in 3 cases. RTB histology and nuclear grade were concordant with final pathology findings in 93% and 94%, respectively.

Of the masses not initially treated with surgery, 230 were managed with active surveillance and 94 underwent thermal ablation. Fifteen patients were referred to an oncologist for systemic therapies. Adverse events (AEs) occurred in 8.5% of cases; in all cases except 1, the AEs were self-limited.

Despite their potential benefits, RTBs have not been widely adopted in the management of RTBs, Dr. Finelli and his colleagues stated. “The lag in uptake is likely due to concerns regarding the lack of sufficient tissue for diagnosis, discordance with final pathology, safety, and, most importantly, the lack of perceived impact on clinical management,” they wrote.

They noted that their results demonstrate that these concerns are exaggerated. “In view of our results, it seems difficult to continue to justify a timid uptake of routine SRM biopsies and the use of this information to implement treatment strategies. … Given the current evidence, it is our strong belief that it is now time to shift the clinical paradigm. We believe that RTB should be considered the initial step in the management of patients with radiographically indeterminate SRMs in whom a therapeutic approach is being considered.”

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