The natural history of renal angiomyolipoma (AML) is unknown. Treatment recommendations are based on smaller case series, with selection bias towards symptomatic patients.
To define the natural history of renal AML, including growth rates, size, and clinical presentation.
We used a unique radiology data-mining system (Montage; Montage Healthcare Systems, Philadelphia, PA, USA) to retrospectively review the radiology database in an academic health centre between 2002 and 2013 to identify all renal AMLs. Of 2741 patients identified, 447 with 582 AMLs had three or more imaging studies suitable for analysis.
Angioembolisation, surgery, radiofrequency ablation, and mammalian target of rapamycin inhibitors.
The primary end point was the growth rate of untreated AMLs. We used a linear mixed-effects model to determine change in growth rate over time. We evaluated the association among growth rate, size, and patient factors as well as interventions.
The majority of untreated AMLs (>92%) had not grown at a median follow-up of 43 mo, with no difference in growth rates between AMLs ≤4 and >4cm. Most AMLs occurred in female participants (80%) and were asymptomatic (91%). Tuberous sclerosis complex (TSC) was confirmed in 3. 8% (n=17) and presented at an earlier age. Median size was 1cm but was significantly larger for TSC (5. 5cm; p<0. 001). Interventions were performed in 5. 6% of patients. Limitations of our study include the retrospective design, selection against fat-poor AMLs, and lack of histology.
This large, single-institution series on AMLs confirms that lesions >4cm do not require early intervention based on size alone. The vast majority are sporadic, asymptomatic, and initially harmless, with a negligible growth rate. Our findings support a policy of initial active surveillance for all asymptomatic AMLs.
We evaluated the natural history and growth rates of renal AMLs. We found no difference in growth rates between AMLs >4 and ≤4cm. Initial AS appears to be a safe management option.
European urology. 2016 Feb 09 [Epub ahead of print]
Jaimin R Bhatt, Patrick O Richard, Nicole S Kim, Antonio Finelli, Karthikeyan Manickavachagam, Laura Legere, Andrew Evans, York Pei, Jenna Sykes, Kartik Jhaveri, Michael A S Jewett
Departments of Surgical Oncology and Surgery (Urology), Princess Margaret Cancer Centre, University Health Network, and the University of Toronto, Toronto, Ontario, Canada; Department of Urology, University Hospital Ayr, Scotland, UK. , Departments of Surgical Oncology and Surgery (Urology), Princess Margaret Cancer Centre, University Health Network, and the University of Toronto, Toronto, Ontario, Canada. , Departments of Surgical Oncology and Surgery (Urology), Princess Margaret Cancer Centre, University Health Network, and the University of Toronto, Toronto, Ontario, Canada. , Departments of Surgical Oncology and Surgery (Urology), Princess Margaret Cancer Centre, University Health Network, and the University of Toronto, Toronto, Ontario, Canada. , Departments of Surgical Oncology and Surgery (Urology), Princess Margaret Cancer Centre, University Health Network, and the University of Toronto, Toronto, Ontario, Canada. , Departments of Surgical Oncology and Surgery (Urology), Princess Margaret Cancer Centre, University Health Network, and the University of Toronto, Toronto, Ontario, Canada. , Department of Pathology, Princess Margaret Cancer Centre, University Health Network, and the University of Toronto, Toronto, Ontario, Canada. , Department of Medicine, Princess Margaret Cancer Centre, University Health Network, and the University of Toronto, Toronto, Ontario, Canada. , Department of Biostatistics, Princess Margaret Cancer Centre, University Health Network, and the University of Toronto. , Joint Department of Medical Imaging, Princess Margaret Cancer Centre, University Health Network, and the University of Toronto, Toronto, Ontario, Canada. , Departments of Surgical Oncology and Surgery (Urology), Princess Margaret Cancer Centre, University Health Network, and the University of Toronto, Toronto, Ontario, Canada.
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