Endophytic Upper Tract Urothelial Carcinoma in a Solitary Kidney Treated by Cryotherapy: An Unorthodox Case for Successful Management - Beyond the Abstract

Renal masses concerning cancer can certainly pose a clinical conundrum for patients with a solitary functional kidney, thus we are motivated to explore more conservative approaches to preserve kidney function in the management of early stage kidney cancer. Cryoablation is one of the ablative modalities with excellent outcomes in the treatment of small renal masses of primary kidney cancer. Studies have shown high survival rates, low recurrence rates, and low complications after cryoablation for masses 3 cm or less.

In this case, we treated a 3.5 cm mass of UTUC through cryoablation. The most recent AUA guidelines for non-metastatic UTUC recommend tumor ablation as the initial management option for patients with low-risk favorable disease (Guideline Statement 13). AUA Guideline Statement 15 for low grade UTUC recommends tumor ablation through a retrograde or anterograde percutaneous approach (Expert Opinion). However, the energy sources described in the supporting studies note the use of thulium, holmium, neodymium (Nd:YAG), or electrocautery to achieve tumor ablation without the mention of cryotherapy. Thus, we believe this case report may serve as an impetus for a potential randomized trial assessing the role of cryotherapy as an energy modality for upper tract tumor ablation.

Tumor grade, multifocality, and a history of bladder cancer have all been reported as predictors of UTUC recurrence however the presented case possessed none of these risk factors. Thus, the nuance of patient selection must again be stressed as this case presented with an approximate 3.5 cm mass on imaging. However favorable characteristics such as possessing a unifocal lesion without obstruction, without lymphadenopathy, and without lower tract involvement highlight the necessity of appropriate staging and risk stratification prior to intervention with curative intent. The presence of this mass in a solitary functioning kidney of an elderly patient at significant risk for progressive chronic kidney disease (CKD) with more aggressive surgical approaches guided treatment toward a more conservative approach. However, the unusual appearance of this solitary endophytic mass complicated the initial diagnosis supporting renal cell carcinoma as the likely etiology, therefore emphasizing the crucial role of mass biopsy to ensure an accurate diagnosis as imaging independently has a variable sensitivity for predicting histology. Of note, on the patient’s subsequent endoscopic examination, there was no visual evidence of any residual UTUC tumor. Again, this patient did not develop disease recurrence in an 8 year follow up period while maintaining his kidney function without CKD progression. Thus, we believe this case report may serve as an impetus for potential utilization of cryotherapy as an energy modality to facilitate upper tract tumor ablation. Future innovations may be tailored toward developing an endoscopic cryotherapy probe to allow for ablation through a ureteroscopic approach.

Written by: Ramy Youssef Yaacoub, MD & Mark Sultan, MD

Department of Urology, University of California Irvine, Orange, CA

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