Enhanced Endoscopic Imaging Technologies in Upper Urinary Tract Urothelial Tumors: Implications for Kidney-Sparing...

Upper tract urothelial carcinoma (UTUC) represents 5-10% of urothelial malignancies and poses significant diagnostic challenges. Ureterorenoscopy (URS) remains essential for definitive diagnosis, tumor characterization, and selection of candidates for kidney-sparing surgery. Recent advances in endoscopic image-enhancement technologies aim to overcome the limitations of conventional white-light URS. The aim of this study is to review the current evidence on advanced endoscopic imaging techniques for the diagnosis and management of UTUC. This narrative literature review summarizes current evidence on advanced endoscopic imaging techniques for UTUC. A comprehensive search of PubMed/MEDLINE, EMBASE, and Scielo databases was conducted to identify studies evaluating photodynamic diagnosis (PDD), narrow band imaging (NBI), Image1-S™-Spies™, optical coherence tomography (OCT), confocal laser endomicroscopy (CLE), and endoluminal ultrasonography (ELUS). Data were qualitatively synthesized by modality. Macroscopic enhancement techniques (PDD, NBI, Image1-S™) improve visualization of urothelial surfaces and vascular patterns during URS. PDD demonstrates the highest diagnostic accuracy, with sensitivities up to 95.8%, and a pooled sensitivity and specificity of 0.96 and 0.86. NBI increases tumor detection rates, identifying up to 22.7% additional lesions in early studies. Microscopic imaging modalities provide complementary information. OCT enables high-resolution cross-sectional imaging with 93% concordance with pathological staging. CLE offers in vivo optical biopsy with near-histological resolution, achieving concordance rates of 100% for low-grade and 83-86% for high-grade tumors. ELUS allows deeper tissue assessment but with lower spatial resolution. Enhanced endoscopic imaging technologies are promising, improving tumor detection, characterization, and intraoperative risk stratification. However, current evidence remains limited and heterogeneous, highlighting the need for large prospective multicenter studies to define their impact on oncological outcomes.