Growth kinetics and short term outcomes of cT1b and cT2 renal masses under active surveillance - Abstract

OBJECTIVES: Compared to T1a lesions, the natural history of untreated renal masses is >4cm is poorly understood.

We sought to assess the growth kinetics and outcomes of cT1b/T2 cortical renal tumors managed with an initial period of active surveillance (AS), and compared these patients to those who underwent definitive delayed intervention.

METHODS: Our institutional, prospectively maintained, renal tumor database was reviewed to identify enhancing solid & cystic masses managed expectantly. Clinically localized tumors >4.0 cm (≥T1b) that were radiographically followed for >6 months were included for analysis. Tumor size at presentation, annual linear tumor growth rate (LGR), Charlson comorbidity index (CCI), length of follow-up (FU), and clinical outcomes were compared between those who remained on AS or those who underwent delayed surgical intervention.

RESULTS: 72 tumors >4cm in diameter (in 68 patients) were identified. 45 patients (66%) were managed solely with AS, while 23 (34%) progressed to intervention. For all lesions, the median tumor size at presentation was 4.9 cm, and the mean LGR was 0.44 cm/year. 14.7% of masses demonstrated no growth over time. Comparing patients managed exclusively with AS and those progressing to definitive intervention, no differences were noted in median tumor size at presentation (4.9 vs. 4.6 cm, p=0.79) or median CCI (3 vs. 2, p=0.6), while significant differences were seen with respect to median age at presentation (77 vs. 60 years, p=0.0002) and mean LGR (0.37 vs. 0.73 cm/year, p=0.02). Following adjustment, younger patients (OR 0.91 [CI 0.86-0.97]) and tumors with faster LGR (OR 9.1 [CI 1.7-47.8]) were more likely to undergo delayed surgical intervention. With a median FU of 32 months (mean, 38.9 ± 24.0; range 6-105), 9 patients died (13%) from other cause and no patient progressed to metastatic disease.

CONCLUSIONS: Localized cT1b or larger renal masses show comparable growth rates to small tumors managed expectantly with low rates of progression to metastatic disease at short term follow up. An initial period of AS to determine tumor growth kinetics is a reasonable option in select patients with significant competing risks and limited life expectancy.

Written by:
Mehrazin R, Smaldone MC, Kutikov A, Li T, Tomaszewski JJ, Canter DJ, Viterbo R, Greenberg RE, Chen DY, Uzzo RG.   Are you the author?
Division of Urologic Oncology, Department of Surgical Oncology, Fox Chase Cancer Center-Temple University Health System, Philadelphia, PA, 19111.  

Reference: J Urol. 2014 Mar 15. pii: S0022-5347(14)02971-1.
doi: 10.1016/j.juro.2014.03.038

PubMed Abstract
PMID: 24641909 Renal Cancer Section