Mieke Bus

44 Chapter 3 Discussion We performed a systematic review of the current literature on optical diagnostics in the upper urinary tract. Only 11 articles were available, most of them were conducted ex-vivo in human or animal. Four articles were available for quality assessment, demonstrating the lack of evidence. All studies are in an initial phase of human research according to IDEAL stages for surgical innovations. All in vivo human studies showed high quality of diagnostic tests and low bias risk. From a clinical point of view, the ideal adjunct modality for endoscopic procedures in the upper urinary tract should 1) detect malignant and premalignant lesions with a high sensi- tivity and specificity, 2) provide real-time reliable information on grade and stage, 3) reliably identify the extension and deep margins in order to achieve complete resection and con- sequently identifies residual tumour within resection margins, 4) be physician friendly; easy to apply with a short learning curve for image interpretation, 5) avoid the use of exogenic contrast agents, 6) preferably be low in costs. (8, 23) URS with conventional biopsy does not meet all of these conditions. Tumour detection and knowledge about grading and staging should be the ultimate diagnostic objective. Therefore, the potential combination of endos- copy with optical diagnostic techniques could increase diagnostic accuracy and improve treatment selection and may reduce costs. NBI, SPIES and PDD aim at improving visualisation of upper urinary tract tumours during ureterorenoscopy. OCT and CLE aim at providing minimal invasive, real-time, objective pre- diction of histopathological diagnosis. However, endoscopy in the upper urinary tract is challenging due to its small diameter and vulnerability of tissues. This environment creates many limitations that have to be overcome before optical diagnostics can be reliably applied in the upper urinary tract. In our opinion, the most optimal optical device should be able to detect urothelial tumours, to provide depth resolved tissue information which allows staging and specific information on bio- chemical or intracellular changes in tissue which allows grading, all in real-time. A combina- tion of NBI, SPIES or PDD with OCT or CLE could be such a real-time optical adjunct modality. Further research needs to be conducted in order to evaluate the true value, before they can be implemented in the management of UTUC. Current available data are too preliminary to evaluate these new technologies and implement them into the diagnostic work-up of patients with UTUC. Therefore, we would plea for more and better conducted studies for the evaluation of diagnostic technologies in the upper urinary tract. Studies on optical technol- ogies in the upper urinary tract involve translation from a biomedical engineering technol- ogy, sometimes already applied in routine care for other specialties e.g. gastroenterology,