The role of Narrow-band Imaging Cystoscopy in Non-muscular Invasive Bladder Cancer Management

IOAN SCARNECIU1,2*, IONUT-ALEXANDRU BANUTA2, CAMELIA CORNELIA SCARNECIU1,2, ADRIAN BRINZA2, LAURIAN MAXIM1,2, ALEXANDRU GEORGIAN LACULICEANU1,2, HODADE DANIEL PORAV3,4, MOGA CIPRIAN TODEA3,4, VERONICA GHIRCA3,4, MARTHA ORSOLYA3,4 1University of Transilvania Faculty of medicine, 56th Nicolae Balcescu Str., 500019, Brasov, Romania 2Clinical Emergency County Hospital, 25-27th Bucuresti Road, 500326, Brasov, Romania 3University of Medicine, Pharmacy, Sciences and Technology of Targu Mures, 38 Gheorghe Marinescu Str., 540139, Targu Mures, Romania 4 Clinical Emergency County Hospital, 1st Gheorghe Marinescu Str., 540103, Targu Mures, Romania

Bladder carcinoma is the most common neoplasm of the urothelial tract. Approximately 75-85% of patients with bladder carcinoma are confirmed with non-muscular invasive bladder cancer (NMIBC) that includes mucosa (Ta and CIS) and submucosa (T1) [1,2]. Smoking is a well-known risk factor for bladder cancer mostly in men, also being a cause for infertility and erectile dysfunction [3,4].
The current diagnostic and therapeutic management for NMIBC is transurethral resection of bladder tumors (TURBT) with white light imaging (WLI). However, small papillary tumors.
or carcinoma in situ (CIS) may easily be missed by WLI [5], and for this cases, new types of imaging are used for the improvement of diagnosis, treatment and a lower rate of recurrence.
A new type of cystoscopy has been used in the last years, using narrow-band imaging (NBI), improving the detection and treatment of NMIBC [6], also decreasing the rate of recurrence, placing narrow-band filters in front of a conventional light source to achieve illumination of tissues of a particular wavelength. This optical technique filters white light into two bands of light in the blue (415nm) and green (540 nm) spectrum, which penetrates tissue only superficially and is strongly absorbed by hemoglobin [7].
The study aimed to determine if NBI can improve the detection of NMIBC and also the management of these cases.

Materials and methods
We performed a prospective study where we compared the two techniques of imaging (WLI and NBI) on a total of 416 patients with ages between 34 and 80 years old presenting known primary or recurrent tumor. The study was conducted between September 2017 and February 2019, using an Olympus NBI system. The technique consisted of evaluating the bladder with WLI and after performing an NBI reevaluation. In all cases, TURBT with biopsy was performed, and the histopathological result indicated NMIBC.
In It is critical for the management of NMIBC to identify all tumor lesions by a new diagnostic technique, detecting low-grade and non-invasive bladder cancer, instead of finding them at a later evaluation with a higher grade and staging [8,9], because they have a risk for progression at five years of 17-45% [9], with invasion of ureteral oriffices and secondary renal failure [10,11] or metastases [12][13][14][15][16][17].
The NBI evaluation and TURBT of NMIBC show that it has fewer subsequent recurrences and longer recurrencefree gap than WLI [45]. Any overlooked tumors will be considered as recurrence at a later evaluation. Two articles that compared the treatment effectiveness using NBI and WLI TURBT shows that the 3-months recurrence rate was 15.0% and 30.5% [46], also 3.9% and 16% [47].
Another study indicates that minimal variations appeared between a novice urologist in NBI and one with more experience, concluding there is no curve in learning NBI cystoscopy and TURBT [48]. The article of Herr et al., proves that variations on an individual level between urologists using NBI has no impact on the quality of NMIBC management [49][50][51][52], but the number of biopsies forms normal mucosa can affect the specificity of the procedure [52][53][54].

Conclusions
This study shows that NBI cystoscopy and TURBT significantly improves the detection of primary and recurrent NMIBC compared to WLI, particularly for Ta and CIS lesions. Patients diagnosed with bladder tumors, investigated throught WLI cystoscopy, had fewer subsequent recurrences and longer recurrence-free intervals when additional investigation, such as NBI cystoscopy, was performed.
The NBI technique increases the contrast between a normal epithelium and a slightly elevated epithelium. In patients with prior bladder instillations, the NBI evaluation must be performed after a safe period of time, to avoid false positive results given by the modification of blood vessel architecture.