Conventional White-light Imaging Research Articles

Narrow-Band Imaging Improves Detection of Colorectal Peritoneal Metastases: A Clinical Study Comparing Advanced Imaging Techniques

BackgroundColorectal peritoneal metastases (PM) are often diagnosed in an advanced disease stage. Cytoreduction and hyperthermic intraperitoneal chemotherapy (HIPEC) improve survival of patients with colorectal PM, although most benefit is seen in patients with limited peritoneal disease. Advanced imaging techniques might improve the detection of PM, potentially leading to earlier diagnosis and improved cytoreduction. This prospective clinical trial compared three advanced techniques with conventional white-light imaging for the detection of colorectal PM: narrow-band imaging (NBI), near-infrared indocyanine green fluorescent imaging (NIR-ICG), and spray-dye chromoendoscopy (SDCE).MethodsPatients with colorectal PM were prospectively included. Prior to cytoreduction and HIPEC, all abdominal regions were inspected with white-light imaging, NBI, NIR-ICG, and SDCE during exploratory laparoscopy. Primary endpoints were sensitivity and specificity for the detection of PM, using pathological examination of biopsied lesions as the reference standard. The safety of all techniques was assessed.ResultsBetween May 2016 and March 2018, four different techniques were analyzed in 28 patients, resulting in 169 biopsies. Sensitivity for the detection of PM significantly increased from 80.0% with white light to 96.0% with NBI (p = 0.008), without loss of specificity (74.8% vs. 73.1%, respectively, p = 0.804). The use of NIR-ICG and SDCE was discontinued after 10 patients had undergone treatment because the lesions were not fluorescent using NIR-ICG, and because SDCE did not visualize the whole peritoneum. No adverse events relating to the imaging techniques occurred.ConclusionNBI substantially increased the detection of PM. This method is safe and could improve the detection of metastatic lesions and help optimize cytoreduction in patients with colorectal PM.

Laryngeal dysplasia and narrow band imaging: Secondary analysis of published data supports the role in patient follow-up.

Clinicians have recognised the role of narrow band imaging (NBI) in the management of head and neck cancer in several studies. However, a recent systematic review was unable to pool the data on diagnostic efficacy in this setting owing to the heterogeneity in the published data. Secondary analysis of data, utilising Bayes' theorem, from meta-analyses and randomised trials. In patients with a histological diagnosis of mild dysplasia who show no abnormalities on NBI, the post-test probability of malignancy is estimated to be 2.3%, compared to 10.3% with conventional white light imaging (WLI). For severe dysplasia, similar post-test probabilities after NBI and WLI are estimated to be 8.0% and 29.7%, respectively. Post-test probabilities in this setting indicate the chance of missing malignancy following a negative NBI or WLI in patients who undergo no further intervention. This study also provides a nomogram designed for use in this setting. This study identifies the evidence base for use of NBI in the follow-up for laryngeal dysplasia.

Linked color imaging enhances endoscopic detection of sessile serrated adenoma/polyps.

Background and study aims Although new image-enhanced endoscopy (IEE) technologies such as blue laser imaging (BLI), BLI-bright, and linked color imaging (LCI) have been developed, their utility for the detection of sessile serrated adenoma/polyps (SSA/Ps) is still unclear. This study aimed to evaluate the utility of BLI, BLI-bright, and LCI for SSA/P detection in still image examinations and in a prospective randomized controlled trial (RCT). Patients and methods A group of 6 expert and non-expert endoscopists read 200 endoscopic still images containing SSA/P lesions using white light image (WLI), BLI, BLI-bright, and LCI. Color differences were calculated using the color space method. A prospective RCT of tandem colonoscopy with WLI and LCI was performed. Patients with SSA/P and those with a history of SSA/P that had been endoscopically removed were enrolled and randomly allocated to WLI-LCI or LCI-WLI groups. Additional endoscopic detection rates for SSA/P were compared between the 2 groups. Results LCI showed the highest SSA/P detection rate among the 4 modes for both expert and non-expert endoscopists. The detection rate with LCI for the 6 expert endoscopists (mean 98.3 ± standard deviation 2.0 %) was significantly higher than that with WLI (86.7 ± 6.0 %, P < 0.01). Likewise, the detection rate with LCI for the 6 non-expert endoscopists (92.3 ± 2.9 %) was significantly higher than that with WLI (72.7 ± 11.5 %, P < 0.01). The color difference of SSA/P with LCI was the highest among the 4 modes, and was significantly higher than with WLI (median 15.9, (interquartile range 13.7 – 20.6) vs. 10.2, (7.6 – 14.2); P < 0.0001). In the RCT, a total of 44 patients (WLI-LCI 22 vs. LCI-WLI 22) underwent colonoscopy. The additional detection rate for SSA/P in the second inspection in the WLI-LCI group (21.6 %, 8/37) was significantly higher than in the LCI-WLI group (3.2 %, 1/31; P = 0.02). The small, flat, non-mucus and isochromatic SSA/Ps in the transverse colon were detected more frequently in the second inspection with LCI. Conclusions LCI was the most sensitive mode for SSA/P detection among WLI, BLI, BLI-bright, and LCI in the still image examinations. Our RCT strongly suggests that LCI is superior to conventional WLI for SSA/P detection during colonoscopy. UMIN000017599.

Autofluorescence and white light imaging-guided endoscopic Raman and diffuse reflectance spectroscopy for in vivo nasopharyngeal cancer detection.

Nasopharyngeal cancer (NPC) is an endemic with high incidence in Southern China and Southeast Asia countries. Screening for NPC under conventional white light imaging (WLI) nasopharyngoscope examination remains a great clinical challenge due to its poor sensitivity. Here, we developed an integrated 4-modality endoscopy system combining WLI, autofluorescence imaging (AFI), diffuse reflectance spectroscopy and Raman spectroscopy technologies for in vivo endoscopic cancer detection for the first time. A pilot clinical test of the system for NPC detection was conducted, in which 283 in vivo Raman and diffuse reflectance spectral data sets from 30 NPC patients and 30 healthy subjects were acquired under the guidance of AFI and WLI. Both high diagnostic sensitivity (98.6%) and high specificity (95.1%) for differentiating cancer from normal tissue sites were achieved using this system combined with principal component analysis-linear discriminant analysis diagnostic algorithm, demonstrating great potential for improving real-time, in vivo diagnosis of NPC at endoscopy.

Validity of conventional endoscopy using "non-extension sign" for optical diagnosis of colorectal deep submucosal invasive cancer.

Background and study aims The non-extension sign relates to a localized increase in thickness and rigidity due to deep submucosal invasive (SM-d: depth of 1000 μm or more) cancer. The present study aimed to evaluate the efficacy of the non-extension sign in assessing the optical diagnosis of colorectal SM-d cancer. Patients and methods We retrospectively analyzed 309 patients with 315 early colorectal cancers that had been endoscopically or surgically resected. The non-extension sign was judged from chromoendoscopy (CE) using conventional white-light imaging with indigo carmine, and is taken to be positive when any one of the findings of rigidity of a circular arc, trapezoid elevation, or converging mucosal folds are seen. We assessed comparing the accuracy of CE, magnifying chromoendoscopy (M-CE), and magnifying narrow-band imaging (M-NBI) for the optical diagnosis of colorectal SM-d cancer. Results Sensitivity, specificity, and accuracy for the diagnosis of SM-d cancer were 66.0 %, 95.8 %, and 86.3 % for CE; 80 %, 90.7 %, and 87.3 % for M-CE; and 65.0 %, 94.4 %, and 85.1 % for M-NBI, respectively. The specificity of CE was significantly higher than that of M-CE ( P = 0.034). The sensitivity of M-CE was significantly higher than that of CE ( P = 0.026). In a comparison of positive and negative groups for the non-extension sign in SM-d cancer, SM invasion was significantly deeper in the positive group than in the negative group (3012.5 μm vs 2002.4 μm, respectively; P < 0.0001) and the rate of lymphovascular invasion was significantly higher in the positive group than in the negative group (63.6 % vs 41.2 %, respectively; P = 0.032). Conclusions The non-extension sign offers high diagnostic specificity for SM-d cancer, and surgery should be considered in patients with a positive non-extension sign.

Clinical Benefits of Transurethral Resection Under Narrow Band Imaging for Non-Muscle Invasive Bladder Cancer

The aim of this study was to reveal the clinical benefits of transurethral resection (TUR) under narrow band imaging (NBI-TUR) for non-muscle-invasive bladder cancer (NMIBC) compared with conventional white light imaging TUR (WLI-TUR). The subjects were 172 patients with NMIBC who were followed for more than 1 year after undergoing TUR with no additional postoperative treatment. In the WLI-TUR group (n=101), lesions that were detected as positive after systematic intravesical observation under WLI were resected completely under WLI. In the NBI-TUR group (n=71), similar observations under WLI were followed by systematic intravesical observation under NBI. After multiple site biopsy under NBI, TUR was performed for all lesions that were detected as positive under NBI. The sensitivity was calculated based on the results of cystoscopy and pathology of multiple site biopsy samples under WLI and NBI in the NBITUR group. The tumor recurrence rate was analyzed in both groups. Background factors did not differ significantly between the two groups, except for the observation period (63.3 months in the WLI-TUR group vs 42.0 months in the NBI-TUR group, p<0.01). The procedure under NBI had significantly higher sensitivity (94.6% vs 75.0%, p<0.01) compared with that under WLI. The recurrence-free rate in the NBITUR group was significantly higher than that in the WLI-TUR group (p=0.013). The tumor recurrencefree rate of NBI-TUR is higher than that of conventional WLI-TUR for patients with NMIBC.

Fluorescence-Guided Surgery.

Surgical resection of cancer remains an important treatment modality. Despite advances in preoperative imaging, surgery itself is primarily guided by the surgeon’s ability to locate pathology with conventional white light imaging. Fluorescence-guided surgery (FGS) can be used to define tumor location and margins during the procedure. Intraoperative visualization of tumors may not only allow more complete resections but also improve safety by avoiding unnecessary damage to normal tissue which can also reduce operative time and decrease the need for second-look surgeries. A number of new FGS imaging probes have recently been developed, complementing a small but useful number of existing probes. In this review, we describe current and new fluorescent probes that may assist FGS.

Autofluorescence for the diagnosis of visceral pleural invasion in non-small-cell lung cancer

This study was conducted to evaluate the accuracy of autofluorescence as a mode of diagnosis for visceral pleural invasion of non-small-cell lung cancer compared with white-light by means of clinical questions to several thoracic surgeons. Eight independent thoracic surgeons evaluated visceral pleural invasion in 25 cases of non-small-cell lung cancer attached to the visceral pleura on lung windows of preoperative computed tomography images. At the first study meeting to evaluate the accuracy of visceral pleural invasion diagnosis using conventional white-light images, the surgeons diagnosed visceral pleural invasion based on information in preoperative computed tomography images, histological types and videos recorded with white-light mode using a thoracoscope. At the second study meeting to evaluate the accuracy of visceral pleural invasion diagnosis using autofluorescence, the same surgeons diagnosed visceral pleural invasion based on information in 2 videos recorded in white-light mode and in autofluorescence mode using the thoracoscope. The overall average sensitivity, specificity and accuracy of visceral pleural invasion diagnosis by white-light versus autofluorescence mode were 64.6% vs 83.3%, 53.9% vs 73.7% and 56.5% vs 76.0%, respectively. The sensitivity, specificity and accuracy of visceral pleural invasion diagnosis was improved through the additional use of the autofluorescence mode compared with the white-light mode alone.

Evaluation of the visibility of early gastric cancer using linked color imaging and blue laser imaging

BackgroundBlue laser imaging (BLI) and linked color imaging (LCI) are the color enhancement features of the LASEREO endoscopic system, which provide a narrow band light observation function and expansion and reduction of the color information, respectively.MethodsWe examined 82 patients with early gastric cancer (EGC) diagnosed between April 2014 and August 2015. Five expert and 5 non-expert endoscopists retrospectively compared images obtained on non-magnifying BLI bright mode (BLI-BRT) and LCI with those obtained via conventional white light imaging (WLI). Interobserver agreement was also assessed.ResultsIn experts’ evaluation of the images, an improvement in visibility was observed in 73% (60/82) and 20% (16/82) of cases under LCI and BLI-BRT, respectively. In non-experts’ evaluation of the images, an improvement in visibility was observed in 76.8% (63/82) and 24.3% (20/82) of cases under LCI and BLI-BRT, respectively. There were no significant differences between experts and non-experts in the evaluation of the images. The improvement in visibility was significantly higher with LCI than with BLI-BRT in experts and non-experts (p < 0.01). With regard to tumor color on WLI, the improvement in the visibility of reddish and whitish tumors was significantly higher than that of isochromatic tumors when LCI was used. The improvement in visibility with LCI was observed in 71% (12/17) and 74% (48/65) of patients with and without Helicobacter pylori (Hp) eradication, respectively; no significant difference in improvement was observed between these groups. The interobserver agreement was good to satisfactory at ≥ 0.62.ConclusionsIn conclusion, our study showed that LCI improved the visibility of EGC, regardless of the level of endoscopists’ experience or Hp eradication in patients, particularly for EGCs with a reddish or whitish color. The improvement in visibility was significantly higher with LCI than that with BLI.

Linked color imaging (LCI), a novel image-enhanced endoscopy technology, emphasizes the color of early gastric cancer.

Background and study aims Linked color imaging (LCI) and blue laser imaging (BLI) are novel image-enhanced endoscopy technologies with strong, unique color enhancement. We investigated the efficacy of LCI and BLI-bright compared to conventional white light imaging (WLI) by measuring the color difference between early gastric cancer lesions and the surrounding mucosa. Patients and methods Images of early gastric cancer scheduled for endoscopic submucosal dissection were captured by LCI, BLI-bright, and WLI under the same conditions. Color values of the lesion and surrounding mucosa were defined as the average of the color value in each region of interest. Color differences between the lesion and surrounding mucosa (ΔE) were examined in each mode. The color value was assessed using the CIE L*a*b* color space (CIE: Commission Internationale d’Eclairage). Results We collected images of 43 lesions from 42 patients. Average ΔE values with LCI, BLI-bright, and WLI were 11.02, 5.04, and 5.99, respectively. The ΔE was significantly higher with LCI than with WLI ( P < 0.001). Limited to cases of small ΔE with WLI, the ΔE was approximately 3 times higher with LCI than with WLI (7.18 vs. 2.25). The ΔE with LCI was larger when the surrounding mucosa had severe intestinal metaplasia ( P = 0.04). The average color value of a lesion and the surrounding mucosa differed. This value did not have a sufficient cut-off point between the lesion and surrounding mucosa to distinguish them, even with LCI. Conclusion LCI had a larger ΔE than WLI. It may allow easy recognition and early detection of gastric cancer, even for inexperienced endoscopists.

Magnified endoscopic observation of small depressed gastric lesions using linked color imaging with indigo carmine dye.

Magnifying linked color imaging with indigo carmine dye (M-Chromo-LCI) enables sterically enhanced and color image-magnified observation of the superficial gastric mucosa. This study investigated the usefulness of M-Chromo-LCI for the differential diagnosis of gastric lesions. 100 consecutive small depressed lesions were examined with conventional white-light imaging (C-WLI), magnifying blue-laser imaging (M-BLI), and M-Chromo-LCI. Endoscopic images were reviewed by three experts and three non-experts. Diagnostic accuracy and interobserver agreement were compared among the modalities. For experts, M-BLI showed a significantly higher diagnostic accuracy than C-WLI (82.7 % vs. 67.0 %; P < 0.001). The diagnostic accuracy of M-Chromo-LCI was not different from M-BLI (87.7 % vs. 82.7 %; P = 0.31). For non-experts, M-BLI showed a significantly higher diagnostic accuracy than C-WLI (69.3 % vs. 52.3 %; P < 0.001). M-Chromo-LCI additionally showed a significantly higher diagnostic accuracy than M-BLI (79.7 % vs. 69.3 %; P = 0.005). M-Chromo-LCI had the highest interobserver agreement for each group. M-Chromo-LCI is expected to become a useful modality for the accurate diagnosis of gastric lesions.

Apllication of high resolution electronic staining endoscopy in the diagnosis of gastrointestinal diseases

I-scan technology is the newly developed image enhanced endoscopy technology from PENTAX, Japan, which can visualize the capillary and the gap of glandular duct of gastrointestinal mucosa. i-scan images are as bright as conventional white-light images. Therefore, i-scan is able to observe much larger areas in a distant view compared with NBI. It has a broad application prospects. However, due to the lack of a unified diagnostic standard, the application of i-scan technology needs further study. This review summarizes the applications of high-resolution electron-staining endoscopy in the diagnosis of gastrointestinal diseases. Key words: Endoscopy, gastrointestinal; Elasticity imaging techniques

Diagnosis of nonexophytic nasopharyngeal lesion with endoscopy-guided core needle biopsy after narrow band imaging.

BackgroundDue to the obstruction of the surrounding structures or stiff mucosa, the primary and recurrent nonexophytic nasopharyngeal carcinoma (NE-NPC) patients are difficult to be diagnosed histologically by traditional forceps biopsy.ResultsAll the 15 cases had adequate biopsy for histological diagnosis. There were 5 cases of primary and 7 cases of recurrent NE-NPC, and 3 cases of inflammatory lesion. The histopathological diagnosis was consistent with the follow-up visit. The bleeding quantity during the CNB procedure ranged from 1 to 5 ml (mean 1.93 mL). The pain score during CNB were between 2 and 7 (mean 4.20). There were no serious complications.Materials and MethodsFrom April 2009 to March 2016, after conventional white-light and novel narrow-band imaging, nasal endoscope-guided core needle biopsy (CNB) were performed on 15 cases of nonexophytic nasopharyngeal lesion with a semiautomatic biopsy gun.ConclusionsCNB is able to get adequate biopsy specimens and thus the diagnosis accuracy of CNB is high for NE-NPC. Nasal endoscope-guided CNB is the direct approach with a short distance in the tissue before reaching the tumor. It has the advantages of minimal trauma, short operative time, and no serious complications. It is simple, safe, and worth of application in clinic.

Direct peroral cholangioscopy for diagnosis of bile duct lesions using an I-SCAN ultraslim endoscope: a pilot study.

UMIN000021009.

Endocytoscopy can be used to assess histological healing in ulcerative colitis.

Background and study aim Endocytoscopy (ECS) is used in the in vivo microscopic inspection of microstructural mucosal features and enables endoscopists to assess the histological severity of ulcerative colitis (UC). The aim of this study was to assess histological healing in UC patients by using ECS. Patients and methods A total of 64 patients in clinical and endoscopic remission who underwent ECS were selected. The correlation between the ECS score and Geboes score at the rectum was evaluated in patients with a Mayo endoscopic score (MES) of 0. The diagnostic accuracy of the ECS score for histological remission (Geboes score ≤ 2) was also assessed. Results The ECS score ranged from 0 to 5 in patients with endoscopic remission on conventional white-light images (MES of 0). The agreement between histological remission regarding the ECS score and the Geboes score had a κ value of 0.72, and the ECS score showed high accuracy for histological remission, with a sensitivity of 0.77, a specificity of 0.97, and a diagnostic accuracy of 0.86. Conclusion ECS can be used to assess histological healing in patients with UC without the need for biopsy specimens.

Su1617 Long-Term Outcomes of “Resect and Discard” Strategy Using Both Conventional White-Light Imaging and Magnifying Narrow-Band Imaging for Small (≤9MM) Colorectal Polyp: A Single-Center Retrospective Study

Su1617 Long-Term Outcomes of “Resect and Discard” Strategy Using Both Conventional White-Light Imaging and Magnifying Narrow-Band Imaging for Small (≤9MM) Colorectal Polyp: A Single-Center Retrospective Study

The adenoma miss rate of blue-laser imaging vs. white-light imaging during colonoscopy: a randomized tandem trial.

Background and study aims The aim of the present study was to determine whether blue-laser imaging (BLI) reduced the miss rate of colon adenomatous lesions compared with conventional white-light imaging (WLI). Patients and methods This was a prospective randomized study of patients undergoing screening and/or surveillance colonoscopy at Saga Medical School, Japan. A total of 127 patients were randomized to tandem colonoscopy with BLI followed by WLI (BLI-WLI group) or WLI followed by WLI (WLI-WLI group). The main outcome measure was the adenoma miss rate. Results The proportion of patients with adenomatous lesions was 62.5 % (40 /64) in the BLI-WLI group and 63.5 % (40 /63) in the WLI-WLI group. The total number of adenomatous lesions detected in the first inspection of the BLI-WLI and WLI-WLI groups was 179 and 108, respectively, compared with 182 and 120 in the second inspection, respectively. The miss rate in the BLI-WLI group was (1.6 %), which was significantly less than that in the WLI-WLI group (10.0 %, P = 0.001). Conclusions Colonoscopy using BLI resulted in a lower colon adenoma miss rate than WLI.Trial registration UMIN 000015677.

Diagnosis of Helicobacter pylori-related chronic gastritis, gastric adenoma and early gastric cancer by magnifying endoscopy.

Evaluating the prevalence and severity of gastritis by endoscopy is useful for estimating the risk of gastric cancer (GC). Moreover, understanding the endoscopic appearances of gastritis is important for diagnosing GC due to the fact that superficial mucosal lesions mimicing gastritis (gastritis-like lesions) are quite difficult to be detected even with optimum preparation and the best technique, and in such cases tissue biopsy is often not very accurate for the diagnosis of gastric epithelial neoplasia. Magnifying endoscopy is a highly accurate technique for the detection of early gastric cancer (EGC). Recent reports have described that various novel endoscopic markers which, visualized by magnifying endoscopy with image-enhanced system (ME-IEE), can predict specific histopathological findings. Using ME-IEE with vessels and surface classification system (VSCS) may represent an excellent diagnostic performance with high confidence and good reproducibility to the endoscopists if performed under consistent conditions, including observation under maximal magnification. The aim of this review was to discuss how to identify high-risk groups for GC by endoscopy, and how to detect effectively signs of suspicious lesions by conventional white light imaging (C-WLI) or chromoendoscopy (CE). Furthermore, to characterize suspicious lesions using ME-IEE using the criteria and classification of EGC based upon VSCS.

Linked color imaging improves endoscopic diagnosis of active Helicobacter pylori infection.

Background and study aims: Linked color imaging (LCI) is a new image-enhanced endoscopy technique using a laser light source to enhance slight differences in mucosal color. The aim of this study was to compare the usefulness of LCI and conventional white light imaging (WLI) endoscopy for diagnosing Helicobacter pylori (H. pylori). Patients and methods: We retrospectively analyzed images from 60 patients examined with WLI and LCI endoscopy between October 2013 and May 2014. Thirty patients had H. pylori infections, and other thirty patients tested negative for H. pylori after eradication therapy. Four endoscopists evaluated the 2 types of images to determine which was better at facilitating a diagnosis of H. pylori infection. Results: H. pylori infection was identified with LCI by enhancing the red appearance of the fundic gland mucosa. The accuracy, sensitivity, and specificity for diagnosing H. pylori infection using WLI were 74.2 %, 81.7 %, and 66.7 %, respectively, while those for LCI were 85.8 %, 93.3 %, and 78.3 %, respectively. Thus, the accuracy and sensitivity for LCI were significantly higher than those for WLI (P = 0.002 and P = 0.011, respectively). The kappa values for the inter- and intraobserver variability among the 4 endoscopists were higher for LCI than for WLI. Conclusions: H. pylori infection can be identified by enhancing endoscopic images of the diffuse redness of the fundic gland using LCI. LCI is a novel image-enhanced endoscopy and is more useful for diagnosing H. pylori infection than is WLI.

The Clinical Research Office of the Endourological Society (CROES) Multicentre Randomised Trial of Narrow Band Imaging–Assisted Transurethral Resection of Bladder Tumour (TURBT) Versus Conventional White Light Imaging–Assisted TURBT in Primary Non–Muscle-invasive Bladder Cancer Patients: Trial Protocol and 1-year Results

BackgroundWhite light (WL) is the established imaging modality for transurethral resection of bladder tumour (TURBT). Narrow band imaging (NBI) is a promising addition. ObjectivesTo compare 12-mo recurrence rates following TURBT using NBI versus WL guidance. Design, setting, and participantsThe Clinical Research Office of the Endourological Society (CROES) conducted a prospective randomised single-blind multicentre study. Patients with primary non–muscle-invasive bladder cancer (NMIBC) were randomly assigned 1:1 to TURBT guided by NBI or WL. InterventionTURBT for NMIBC using NBI or WL. Outcome measurements and statistical analysisTwelve-month recurrence rates were compared by chi-square tests and survival analyses. Results and limitationsOf the 965 patients enrolled in the study, 481 patients underwent WL-assisted TURBT and 484 patients received NBI-assisted TURBT. Of these, 294 and 303 patients, respectively, completed 12-mo follow-up, with recurrence rates of 27.1% and 25.4%, respectively (p=0.585, intention-to-treat [ITT] analysis). In patients at low risk for disease recurrence, recurrence rates at 12 mo were significantly higher in the WL group compared with the NBI group (27.3% vs 5.6%; p=0.002, ITT analysis). Although TURBT took longer on average with NBI plus WL compared with WL alone (38.1 vs 35.0min, p=0.039, ITT; 39.1 vs 35.7min, p=0.047, per protocol [PP] analysis), lesions were significantly more often visible with NBI than with WL (p=0.033). Frequency and severity of adverse events were similar in both treatment groups. Possible limitations were lack of uniformity of surgical resection, data on smoking status, central pathology review, and specific data regarding adjuvant intravesical instillation therapy. ConclusionsNBI and WL guidance achieved similar overall recurrence rates 12 mo after TURBT in patients with NMIBC. NBI-assisted TURBT significantly reduced the likelihood of disease recurrence in low-risk patients. Patient summaryUse of a narrow band imaging technique might provide greater detection of bladder tumours and subsequent treatment leading to reduced recurrence in low-risk patients.