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

Abstract

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 (GRi) and GR from the prior image (GRp). 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 GRi (–0.0001 cm/yr, 95% confidence interval [CI] –0.007 to 0.007, p = 0.97) or GRp (0.008 cm/yr, 95% CI –0.004 to 0.020, p = 0.17) after adjustment. The only age thresholds associated with an increased GR were 65 yr for GRi and 70 yr for GRp. 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.

Keywords

• Small renal mass
• Active surveillance
• Tumor growth
• Natural history
• Age
• Geriatrics