Evaluation of Growth Rates for Small Renal Masses in Elderly Patients Undergoing Active Surveillance.

Background: As the adoption of active surveillance (AS) for small renal masses (SRMs) grows, the number of elderly patients enrolled for a prolonged period of time will increase. However, our understanding of comparative growth rates (GRs) in aging patients with SRMs remains poor.

Objective: To examine whether particular age cutoffs are associated with an increased GR for patients undergoing AS for SRMs.

Design Setting And Participants: We identified all patients with SRMs enrolled in the multi-institutional, prospective Delayed Intervention and Surveillance for Small Renal Masses (DISSRM) registry since 2009 who elected for AS.

Outcome Measurements And Statistical Analysis: Two definitions of GR were examined: GR from the initial image (GR) and GR from the prior image (GR). Image measurements were dichotomized based on patient age at the time of imaging. Multiple age cutoffs were examined: 65, 70, 75, and 80 yr. Mixed-effect linear regression examined the associations between age and GR, with controlling to account for multiple measurements from the same individual.

Results And Limitations: We examined 2542 measurements from 571 patients. The median age at enrollment was 70.9 yr (interquartile range [IQR] 63.2-77.4) with a median tumor diameter of 1.8 cm (IQR 1.4-2.5). As a continuous variable, age was not associated with GR (-0.0001 cm/yr, 95% confidence interval [CI] -0.007 to 0.007,  = 0.97) or GR (0.008 cm/yr, 95% CI -0.004 to 0.020,  = 0.17) after adjustment. The only age thresholds associated with an increased GR were 65 yr for GR and 70 yr for GR. Limitations include the one-dimensional nature of the measurements used.

Conclusions: Increased age for patients on AS for SRMs is not associated with increased GRs.

Patient Summary: We examined whether patients undergoing active surveillance (AS) exhibited accelerated growth of their small renal masses (SRMs) after a certain age. No demonstrable change was seen, suggesting that AS is a safe and durable management option for aging patients with SRMs.