Growth Kinetics of Small Renal Masses on Active Surveillance: Variability and Results from the DISSRM Registry

Active surveillance (AS) is emerging as a safe and effective strategy for the management of small renal masses (SRMs; ≤4cm). We characterize growth rates (GRs) and their pertinence to clinical outcomes in a prospective multi-institutional study of patients with SRMs.

Since 2009, the Delayed Intervention and Surveillance for Small Renal Masses (DISSRM) prospective multi-institutional registry of patients with SRMs has enrolled patients choosing either primary intervention or AS. Patients electing AS received regularly scheduled imaging, and those with ≥3 follow-up images were included in the current study to evaluate GRs.

A total of 318 patients electing AS were evaluated. 271 (85.2%) had ≥3 follow-up images with median imaging follow-up of 1.83 years. Overall mean SRM GR was 0.09 ±1.51cm/year (median 0.09cm/year) with no variables demonstrating statistically significant associations. GR and variability decreased with longer duration of follow-up (0.54cm/year at <6 months; 0.07cm/year for >1 year). No patients developed metastatic disease or died from kidney cancer. No statistically significant difference was noted in GR for patients with biopsy-demonstrated renal cell carcinoma or for those who died.

SRM growth kinetics are highly variable early on AS, with both GR and variability decreasing with time. Early in AS, especially the initial 6-12 months, GR is variable and does not reliably predict death or adverse pathological features for the subset with available pathology. An elevated GR may indicate need for further assessment with imaging or consideration of biopsy prior to progressing to treatment. Additional follow-up will inform the best clinical pathway for elevated GRs.

The Journal of urology. 2017 Sep 23 [Epub ahead of print]

Akachimere C Uzosike, Hiten D Patel, Ridwan Alam, Zeyad R Schwen, Mohit Gupta, Michael A Gorin, Michael H Johnson, Heather Gausepohl, Mark F Riffon, Bruce J Trock, Peter Chang, Andrew A Wagner, James M McKiernan, Mohamad E Allaf, Phillip M Pierorazio

Included In: Badrinath Konety, MD 2018 AUA Presentation: Journal of Urology: Top Papers in Bladder and Renal Cancer