ORLANDO, FL Active surveillance appears to be a safe alternative to primary intervention for selected patients with small renal masses, according to findings presented at the 2017 Genitourinary Cancers Symposium.1

“Active surveillance is a management option for patients with small renal masses who desire to avoid surgery or defer immediate treatment,” explained Ridwan Alam, a medical student and MPH candidate at Johns Hopkins University School of Medicine in Baltimore, Maryland. “Active surveillance can prevent overtreatment of benign tumors or clinically insignificant cancer and avoid associated risks of treatment.”

To compare active surveillance with primary intervention for small renal masses, researchers prospectively enrolled 615 patients with clinical stage T1 solid renal masses no larger than 4.0 cm into the Delayed Intervention and Surveillance for Small Renal Masses (DISSRM) registry at 3 large academic centers in New York, Boston, and Baltimore (ClinicalTrials.gov Identifier: NCT02346435).

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After counseling, 51.5% of patients opted for active surveillance and 48.5% underwent primary intervention with surgery, ablation, or another option. Patients receiving active surveillance underwent axial imaging at enrollment with alternating ultrasound and axial imaging every 6 to 12 months. Investigators recommended intervention upon evidence of progression, defined as: a growth rate of more than 0.5 cm per year, tumor diameter larger than 4.0 cm, presence of metastatic disease.

“Patients may choose to withdraw or crossover to delayed intervention at their own discretion,” Mr Alam added.

At baseline, patients who chose to undergo active surveillance were significantly older (70.8 vs 61.8 years; P < .001), had significantly worse ECOG performance statuses (P = .02), and had significantly smaller tumors with respect to diameter (P < .001) and volume (P < .001) than those who chose primary intervention.

After a median follow-up of 3.0 years, the median growth rate was determined to be 0.09 cm per year in the active surveillance group.

“Variability in growth rate is high within the first year of imaging and decreases with longer follow-up,” said Mr Alam.

At 7 years, there was no significant difference in cancer-specific survival between the 2 groups (100% with active surveillance vs 98.9% with primary intervention; P = .3). Overall survival was, however, significantly worse in the active surveillance arm than the primary intervention arm (62.8% vs 85.1%; P = .001). Age and ECOG performance status were predictive of all-cause mortality.

“Cancer-specific survival is excellent and comparable in both groups,” said Mr Alam. “Overall survival is worse in the surveillance group, and this is attributable to older age and worse health.”

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The investigators plan to validate the previously developed DISSRM score, an objective point-based selection criteria based on age, ECOG score, tumor size, dementia, and cardiovascular index, to determine the appropriateness of active surveillance for eligible candidates. They will also evaluate quality of life between the 2 groups.

“Active surveillance is not inferior to primary intervention in the intermediate-term, with cancer-specific and metastasis-free survival being excellent,” concluded Mr Alam. “Active surveillance for small renal masses is safe.”


  1. Alam R, Patel HD, Riffon MF, et al. Intermediate-term outcomes from the DISSRM registry: A prospective analysis of active surveillance in patients with small renal masses. Paper presented at: 2017 Genitourinary Cancers Symposium; February 16-18, 2017; Orlando, FL.