Magnifying chromoendoscopy for the detection of premalignant gastrointestinal lesions

A multicenter randomized comparison between high-definition white light endoscopy and narrow band imaging for detection of gastric lesions

OBJECTIVE

Narrow band imaging (NBI) is generally considered to be useful for lesion characterization, but not enhanced detection of gastric lesions, because of the dark endoscopic view. We tested whether the new generation of NBI (190-NBI or 290-NBI), which is twice as bright as the previous version, would improve detection of premalignant gastric lesions compared with high-definition white light endoscopy (HD-WLE).

PATIENTS AND METHODS

This was a multicenter prospective randomized study involving five tertiary institutions in the Asia-Pacific region. A total of 579 patients aged older than 50 years who underwent diagnostic upper gastrointestinal endoscopy were randomized to either HD-WLE or NBI. The outcome measurements were detection of intestinal metaplasia (IM), focal gastric lesions, and gastric cancers.

RESULTS

Focal gastric lesions were detected in 83/286 (29%) and 119/293 patients (40.6%) by HD-WLE and by NBI, respectively (P=0.003). IM was detected in 22/286 patients (7.7%) by HD-WLE and in 52/293 patients (17.7%) by NBI (P<0.001). Gastric cancer were found in 7/286 (2.4%) and 3/293 patients (1%) in HD-WLE and NBI groups, respectively (P=0.189).

CONCLUSION

NBI increased the detection rate of IM compared with HD-WLE.

Dual optical modality endoscopic imaging of cancer development in the mouse colon

BACKGROUND AND OBJECTIVE

We utilize a miniature, dual-modality endoscope that combines fluorescence-based surface magnifying chromoendoscopy (SMC) and optical coherence tomography (OCT) to follow the anatomical changes that occur during adenoma development in the mouse colon.

MATERIALS AND METHODS

Twenty-five mice were treated with the carcinogen azoxymethane (AOM) to induce tumor development in the distal colon, or were treated with saline as control, and were imaged over six months. OCT detects adenoma number with high sensitivity and specificity and can measure lesion size. In methylene blue-lavaged colons, SMC detects changes in the colonic crypts. SMC images of control mouse colons exhibit reticulated patterns of crypts of equal size, forming either a dot or honeycomb pattern.

RESULTS

Images of AOM-treated colons show mild crypt irregularities even in grossly normal tissue. Images of small to medium adenoma exhibit larger crypts, more intense signal, and irregular spacing whereas those of large adenoma have heterogeneous, intense signal and loss of crypt structure.

CONCLUSIONS

The combination of OCT and SMC permits the detection of neoplastic events from the earliest stages of crypt irregularities before gross tissue changes are noted, through to measuring the growth of protruding adenoma.

Progress in diagnosis and treatment of precancerous lesions and early gastric cancer

Gastric cancer is the fourth most prevalent cancer worldwide and the second cause of cancer-related death. The 5-year survival rate for early gastric cancer after treatment is 84%-99%. Early detection and treatment of precancerous lesions are pivotal to improved patient survival. The development of various endoscopic (e.g., endoscopic ultrasound, narrowband imaging, magnifying endoscopy and chromoendoscopy), imaging and laboratory technologies has significantly improved the rate of diagnosis of early cancer and precancerous lesions. In addition, endoscopic techniques (e.g., endoscopic submucosal dissection) and minimally invasive surgery (e.g., laparoscopy) make the therapy of early cancer and precancerous lesions better and less invasive, reduce the incidence of postoperative complications, and improve the quality of life of patients after surgery.

Treatment strategy for gastric non-invasive intraepithelial neoplasia diagnosed by endoscopic biopsy

Treatment strategies, whether as follow-up or “total incisional biopsy” for gastric noninvasive intraepithelial neoplasia diagnosed by examination of an endoscopic forceps biopsy specimen, are controversial due to problems associated with the diagnostic accuracy of endoscopic forceps biopsy and questions about the safety and efficacy of endoscopic treatment. Based on the histological findings of the biopsy specimen, it is difficult to differentiate between reactive or regenerative changes, inflammation and neoplastic changes, intraepithelial and invasive tumors. Therefore, gastric neoplasia diagnosed as noninvasive intraepithelial often develop into invasive carcinoma during follow-up. Recent advances in endoscopic modalities and treatment devices, such as image-enhanced endoscopy and high-frequency generators, may make endoscopic treatment, such as endoscopic submucosal dissection (ESD), a therapeutic option for gastric intraepithelial neoplasia, including low-grade neoplasms. Future studies are required to evaluate whether ESD is a valid strategy for gastric intraepithelial neoplasm with regard to safety and cost effectiveness.

Management of cancer risk in Barrett's esophagus

The importance of Barrett's esophagus (BE) lies in its potential to give rise to esophageal adenocarcinoma (EAC), postulated to be through a series of progressive degrees of dysplasia; from intestinal metaplasia to low-grade dysplasia, high-grade dysplasia, and subsequently, to cancer. The management strategies for the detection and treatment of dysplasia and early esophageal cancer on a background of BE have changed significantly in the last few decades, with the emergence of newer and less invasive non-operative alternatives. This review aims to outline BE and its relation to EAC, the rationale and cost-effectiveness of both screening and surveillance programs, methods of diagnosing and identifying dysplasia and early cancer in Barrett's, and approaches to individualizing their endoscopic and surgical management based on best-available staging techniques.

The future of bronchoscopy in diagnosing, staging and treatment of lung cancer

Bronchoscopy is a central technique in diagnosing lung cancer, but also in different therapeutic approaches. A lot of techniques are available. The most common indication for bronchoscopy is for tissue sampling and determining the extent of lung cancer. Established diagnostic techniques are forceps biopsy, aspiration or brush cytology sampling, or needle aspiration. Laser therapy, electrocautery, cryotherapy and stenting are well-described techniques for the palliation of symptoms due to airway involvement in patients with advanced stages. Newer technologies, with an established role in clinical practice, are endobronchial ultrasound, autofluorescence bronchoscopy, and electromagnetic navigation. Other technologies, such as magnification, narrow-band imaging and confocal fluorescence microendoscopy, are in development for the use within the airways.