NBI system has been recently incorporated by Olympus in the digital ureteroscopes (namely, URF-V and URF-V2). As described in the field of bladder cancer, the current technique is expected to help clinicians in the diagnosis of early urothelial carcinoma and particular condition, such as carcinoma in situ. Indeed, due to the microvascular component characterising malignant lesion, flat lesion can be clearly distinguished from edematous lesions caused for instances by JJ stent, appearing as “frog’s eggs” (see Fig. 11.3).

The first report regarding the use of such a technique in the field of endoscopic treatment of UUT-TCC came from Tenon University Hospital’s experience. Data coming from 27 patients were analyzed. Any area in the NBI mode which appeared as discordant by either blood vessel concentration or appearance (i.e., dotted, tortuous, large-calibre, abrupt-ending vessels) as compared to white-light mode was considered as an abnormal appearance suspected of being malignant lesion. NBI technology allowed to diagnose and clearly visualise UUT-TCC and to identify the extended tumour limits (see Fig. 11.4).

When comparing the endoscopic results with bioptic findings, there were 35 pathologically confirmed transitional cell tumours detected. NBI diagnosed five tumours missed at WL (14.2 %) and clearly identified the edges of three tumours (8.5 %), improving tumour detection rate by 22.7 % [11].

However, no specimens were taken from the extended margins of the tumours that were only visible by NBI, therefore the authors were not able to confirm the hypothesis that such a technique helps clinicians to discriminate tumour limits.

Taken together, these preliminary findings may be the basis for developing further studies aimed at confirming the benefit of NBI not only in the diagnosis but also in the long term treatment of UUT-TCC. Indeed, the impact of NBI technology on the risk of tumour recurrence and progression over time in these patients has still to be determined.

5-ALA plays a natural role in the biosynthetic pathway of heme. Indeed, it is the metabolic precursor of protoporphyrin IX (PpIX), which is the only fluorescent substance in the pathway. The step from protoporphyrin IX (PpIX) to heme, which include the insertion of a ferrous ion into the porphyrin ring, is the critical bottleneck of the whole pathway. Therefore, an exogenous administration of 5-ALA will induce elevated intracellular level of PpIX and consequently an increased fluorescence staining activity arising from neoplastic or highly proliferating cells [13, 14]. This phenomenon has been used by clinicians to better identify malignant and premalignant lesions during endourological procedures. The fluorescent-mode light used is the blue light, which serves as a reference for the normal urothelium, while the tissue accumulating the compound appears as red (see Fig. 11.5).