Survival of Patients With Small Renal Masses Undergoing Active Surveillance
abstract
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Access this abstract nowOBJECTIVES
To determine conditional survival for patients with small renal masses (SRMs) undergoing active surveillance (AS).
MATERIALS AND METHODS
Patients were enrolled in a prospective AS protocol at our institution between May 2005 and January 2016. Patients with SRMs ≤4 cm with serial cross-sectional imaging available in-house for review were included. Overall survival (OS) was estimated using the Kaplan-Meier method and modelled via Cox proportional hazards models. The primary endpoints analysed were the conditional probability of survival and tumour growth over time. Landmark analysis was used to evaluate survival outcomes beyond the 2-year mark after the initial scan. The relative conditional survival of patients on AS was compared to those undergoing partial nephrectomy (PN) using inverse probability of treatment weighting.
RESULTS
A total of 272 patients were included in this analysis. The mean initial SRM size was 1.74 ± 0.77 cm, and the mean mass size closest to the 2-year mark was 1.97 ± 0.83 cm. The likelihood of continued survival to 5 years improved after the 2-year landmark. Patients with masses <3 cm who survived the first 2 years on AS had a 0.84-0.85 chance of surviving to 5 years, and if they survived 3 years, the probability of surviving to 5 years improved to 0.91. A slow tumour growth (β: 0.12; P < 0.001) with parallel growth rates was found for tumours <3 cm. Patients on AS and those who underwent PN had similar OS for ~7 years, beyond which PN demonstrated a trend of lower risk of death compared with AS (hazard ratio 0.57; P = 0.07).
CONCLUSIONS
The conditional survival probability of patients with SRMs <3 cm on AS increased after 2 years. This information may prove useful to urologists and patients who are considering continuing AS vs intervention after the first 2 years on AS.
Additional Info
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Conditional Survival of Patients With Small Renal Masses Undergoing Active Surveillance
BJU Int 2019 Mar 01;123(3)447-455, FG Petros, AM Venkatesan, D Kaya, CS Ng, BM Fellman, JA Karam, CG Wood, SF MatinFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
This article was designed to evaluate the conditional survival of patients with small renal masses on active surveillance (AS), and reports improved survival from the 2-year point moving forward. This will help inform patients and physicians about continued management on AS as the years pass by. Mean tumor size at initiation of AS was only 1.74 cm; so, this was a carefully selected patient population for AS. The overall cancer-specific survival was 98%. Patients with initial tumor size <3.0 cm had the best outcomes.
The study substantiates strong outcomes for AS in appropriately selected patients and confirms that most small renal masses are not “ticking time bombs,” as some patients presume. Improved conditional survival after 2 years may be related to filtering out some of the bad actors but also reflects the indolent tumor biology of many small renal masses.