A step-by-step guide to approaching colon polyps

Colorectal cancer (CRC) is considered one of the most prevalent cancers among Iranian men and women (1). Colorectal polyps, known as precursors of CRCs, are of great importance. Surveillance, locating, and removal of colorectal polyps make them the most modifiable factor apart from other genetic and environmental factors leading to CRCs. Colorectal polyps are defined as outpouchings from superficial and deep layers of mucosa of the colonic wall. They are classified as adenomas, serrated polyps, hyperplastic polyps, and hamartomas based on histological evaluation. Submucosal invasion precludes the possibility of endoscopic resection and should be ruled out via colonoscopic evaluation (2). Knowing this significance, the present study aims to present a brief review on classification, probability of endoscopic resection, complications of endoscopic polypectomy, as well as proper surveillance after polypectomy.

Comparison of the diagnostic performance of NBI, Laser-BLI and LED-BLI: a randomized controlled noninferiority trial

BACKGROUND AND AIMS

New image-enhanced endoscopy (IEE), blue Light Imaging (LED-BLI) is launched in USA and Europe, whereas Blue Laser Imaging (Laser-BLI) is available only Asian and some countries. No studies have directly compared the diagnostic accuracy of narrow band imaging (NBI), Laser-BLI and LED-BLI for colorectal tumors. The present study aimed to compare the diagnostic accuracy of the three methods for colorectal tumor using the NBI international colorectal endoscopic (NICE) classification and the Japanese NBI Expert Team (JNET) classifications.

METHODS

This was a multi-center evaluator-blinded, randomized control trial of patients who underwent endoscopic colorectal tumor resection. The patients were randomly assigned to NBI, Laser-BLI or LED-BLI. Cropped images were sent to blinded external evaluators and diagnosed according to NICE and JNET classifications. The diagnostic accuracy of each endoscopy system was compared with non-inferiority test.

RESULTS

A total of 619 colonic tumors were resected from 230 patients and evaluated by external four evaluators. The diagnostic accuracy of NBI for NICE 1, NICE 2, NICE 3 was 90.6%, 90.3% and 99.5%, respectively and for JNET 1, JNET 2A, JNET 2B and JNET 3, it was 94.6%, 72.0%, 79.2% and 99.1%, respectively. In non-inferiority test, Laser-BLI and LED-BLI revealed non-inferiority to NBI in all NICE and JNET categories (p<0.001).

CONCLUSIONS

Laser-BLI and LED-BLI had high diagnostic accuracy and non-inferiority of NBI, especially for hyperplastic polyp/sessile serrated lesion and low-grade dysplasia. This is first trial to compare the diagnostic accuracy with NBI, Laser-BLI and LED-BLI and useful to understand the position of each IEE. This trial was registered as UMIN000032107.

ESD and Pit Pattern Diagnosis: Lessons from a Japanese Endoscopist Working in the United States

Endoscopic submucosal dissection (ESD) was developed in 2000s to overcome the limitations of endoscopic mucosal resection (EMR), especially to accomplish en-bloc resection, and it has been accepted worldwide in the past decades. Many ESD devices and diagnosis modalities are currently available, which include pit pattern and narrow band imaging (NBI) diagnoses to evaluate the depth of the tumor preoperatively with sensitivities of 70 to 90%. Depending on the Japanese colorectal guideline, the intramucosal cancer and shallow invasion of the submucosal layer are the main good indications of ESD; however, the ESD practices between Japan and Western countries still vary, including pathologic definition of cancer, tumor/node/metastasis classification, and handling of ESD specimen. In the United States, despite the large demand for treatment of colorectal neoplasm, pit pattern and magnified NBI diagnoses are not widely accepted yet, and piecemeal EMR is still the major method in most of the institutions. Moreover, the specific guideline of ESD is also not available yet. More new technologies are being developed other than conventional ESD methods in Eastern and Western countries, and ESD is now expected to change in the next generation. It is recommended that not only gastroenterologists but also colorectal surgeons have appropriate knowledge of colorectal lesions and their management to ensure current treatments is applied to patients.

Can Non-expert Physicians Use the Japan Narrow-band Imaging Expert Team Classification to Diagnose Colonic Polyps Effectively?

Objectives:

In 2014, the Japan narrow-band imaging expert team (JNET) proposed the first unified colorectal narrow-band imaging magnifying classification system, the JNET classification. The clinical usefulness of this system has been well established in JNET member institutions, but its suitability for use by “non-expert physicians” (physicians with no expertise in the use of JNET classification) remains unclear. This study aimed to examine the clinical usefulness of the JNET classification by “non-expert physicians”.

Methods:

We retrospectively analyzed 852 consecutive patients who underwent screening colonoscopy following a positive fecal occult blood test between January 2017 and May 2018. Endoscopic results from colon polyp diagnosis by physicians who started using the JNET classification (JNET group) were compared with those of physicians who did not (control group). Mann-Whitney U test and Fisher's exact test were used to compare continuous and categorical variables, respectively.

Results:

The median patient age was 68 years, and the male-to-female ratio was 1:0.84. When no lesions were found, the median withdrawal time was significantly different between groups (JNET group: 12 min; control group: 15 min; P < 0.01). The number of resected adenomas per colonoscopy was significantly higher in the JNET group (1.7) than in the control group (1.2; P < 0.01). Among the resected lesions, 8.9% in the JNET group and 17% in the control group were non-neoplastic lesions that did not require resection (P < 0.01).

Conclusions:

Colon polyp diagnosis using the JNET classification can reduce unnecessary resection during magnifying colonoscopy when conducted by “non-expert physicians”.

Clinical usefulness of magnifying colonoscopy for the diagnosis of ulcerative colitis-associated neoplasia

BACKGROUND AND AIM

The aim of this investigation was to evaluate the efficacy of Japanese magnifying colonoscopic classifications for ulcerative colitis-associated neoplasia (UCAN).

METHODS

We reviewed the colonoscopy records from 2011 to 2018 at our institutions and identified cases of endoscopically or surgically resected UCAN observed by magnifying narrow-band imaging (NBI) endoscopy and magnifying chromoendoscopy. Association between magnifying endoscopic classification and histopathological findings was investigated retrospectively. Japan NBI expert team (JNET) classification and pit pattern classification were applied.

RESULTS

There were 17 patients who had a diagnosis of UCAN. Tumors of types 2A, 2B and 3 by JNET classification correlated with the histopathological findings of low-grade dysplasia (LGD)/high-grade dysplasia (HGD), HGD, and massively submucosal invasive (mSM) carcinoma, respectively. Tumors of types III/IV, V_I low irregularity, and V_I high irregularity/V_N by pit pattern classification were correlated with the histopathological findings of LGD/HGD, HGD, and mSM carcinoma, respectively.

CONCLUSIONS

Japan NBI expert team classification and pit pattern classification may be predictive of the histological diagnosis and invasion depth of UCAN. This needs to be investigated prospectively in a large cohort or in a randomized clinical trial.

Advanced diagnostic endoscopy in the lower gastrointestinal tract: A review of JGES core sessions

At each of the 89th to the 92nd congresses of the Japan Gastroenterological Endoscopy Society, a series of featured discussion sessions concerning advanced diagnostic endoscopy in the lower gastrointestinal tract were presented. In total, 45 lectures were presented in this subject area. It was shown that, in recent years, several convenient and less invasive colonoscopic modalities have been developed. This review article summarizes these core sessions and the efficacy of the techniques discussed.