Bryan et al. [4] were the first to describe the results of flexible NBI cystoscopy in 29 patients with recurrent bladder tumors. They found 15 additional tumors in 12 patients compared with WLI cystoscopy. Table 2.1 lists results from nine series, all showing enhanced detection of tumors using NBI diagnostic cystoscopy [4–12]. Although the series by Zhu et al. [11] included only 12 patients, they were evaluated by NBI for positive urine cytology and negative WLI cystoscopy. NBI found evidence of carcinoma in situ in 5 (42 %) patients. Collectively, the studies show superior sensitivity and negative predictive value (>90 %) for NBI over WLI cystoscopy, making it useful for identifying abnormal lesions and for excluding a diagnosis of bladder tumor. Although more negative biopsies of false-positive lesions (lower specificity) occurred with NBI, this is not believed to be significant or detrimental, since many patients have denuded mucosa and positive urine cytology, indicating carcinoma in situ (CIS), and additional biopsies have not led to increased toxicity. Negative tumor margins of suspicious lesions indicated by NBI also confirm a complete resection. Table 2.2 shows NBI enhances detection of biopsy-proved carcinoma in situ.