Comparison of different virtual chromoendoscopy classification systems for the characterization of colorectal lesions

Impact of narrow band imaging in prediction of histology of advanced colorectal neoplasia

We assessed the diagnostic performance of the Narrow-Band Imaging (NBI) International Colorectal Endoscopic Classification (NICE) and the Japan NBI Expert Team classification (JNET) in predicting histological outcomes of advanced colorectal lesions. Additionally, we evaluated the sensitivity and positive predictive value (PPV) of the JNET and NICE classifications individually for high-grade lesions (including HGD adenomas, intramucosal carcinomas, and T1 carcinomas). This was a retrospective analysis of prospectively collected data, involving 211 patients (130 men, mean age 60 years) who underwent colonoscopy with endoscopic resection of advanced colorectal neoplasia (lesions ≥ 10 mm). Lesions were classified using both NICE and JNET criteria, and final histopathological results were used for comparison. Of the 257 lesions analyzed, the NICE classification accurately classifies a large proportion of lesions (93.8%). In JNET classification we observed 77.4% correctly classified lesions. Specifically, the sensitivity and positive predictive value (PPV) of the NICE classification for high-grade lesions were 100% and 24.4%, respectively. For the JNET classification, the sensitivity and PPV for high-grade lesions were 56.6% and 57.7%, respectively. The JNET classification, with a positive predictive value of 57.7% for high-grade colorectal lesions (including HGD adenomas, intramucosal carcinomas, and T1 carcinomas), should be used for decision-making regarding appropriate subsequent endoscopic therapy.

Mucosal imaging in colon polyps: New advances and what the future may hold

An expanding range of advanced mucosal imaging technologies have been developed with the goal of improving the detection and characterization of lesions in the gastrointestinal tract. Many technologies have targeted colorectal neoplasia given the potential for intervention prior to the development of invasive cancer in the setting of widespread surveillance programs. Improvement in adenoma detection reduces miss rates and prevents interval cancer development. Advanced imaging technologies aim to enhance detection without significantly increasing procedural time. Accurate polyp characterisation guides resection techniques for larger polyps, as well as providing the platform for the “resect and discard” and “do not resect” strategies for small and diminutive polyps. This review aims to collate and summarise the evidence regarding these technologies to guide colonoscopic practice in both interventional and non-interventional endoscopists.

Colorectal malignant polyps: a modern approach

Colorectal malignant polyps (MP) are polyps with invasive cancer into the submucosa harboring a variable risk of lymph node involvement, which can be estimated through evaluation of morphological, endoscopic, and histologic features. The recent advances in imaging endoscopic techniques have led to the possibility of performing an optical diagnosis of T1 colorectal cancer, allowing the selection of the best therapeutic modality to optimize outcomes for the patient. When MP are diagnosed after endoscopic removal, their management can be challenging. Differentiating low- and high-risk histologic features that influence the possibility of residual tumor, the risk of recurrence and the risk of lymph node metastasis, is crucial to further optimize treatment and surveillance plans. While the presence of high-risk features indicates a need for surgery in the majority of cases, location, comorbidities and the patient’s preference should be taken in account when making the final decision. This is a particularly important issue in the management of low rectal MP presenting with high-risk features, where chemoradiotherapy followed by a watch-and-wait strategy has demonstrated promising results. In this review we discuss the important prognostic features of MP and the most modern approaches regarding their management.

External validation of blue light imaging (BLI) criteria for the optical characterization of colorectal polyps by endoscopy experts

BACKGROUND AND AIM

Recently, the BLI Adenoma Serrated International Classification (BASIC) system was developed by European experts to differentiate colorectal polyps. Our aim was to validate the BASIC classification system among the US-based endoscopy experts.

METHODS

Participants utilized a web-based interactive learning system where the group was asked to characterize polyps using the BASIC criteria: polyp surface (presence of mucus, regular/irregular and [pseudo]depressed), pit appearance (featureless, round/non-round with/without dark spots; homogeneous/heterogeneous distribution with/without focal loss), and vessels (present/absent, lacy, peri-cryptal, irregular). The final testing consisted of reviewing BLI images/videos to determine whether the criteria accurately predicted the histology results. Confidence in adenoma identification (rated "1" to "5") and agreement in polyp (adenoma vs non-adenoma) identification and characterization per BASIC criteria were derived. Strength of interobserver agreement with kappa (k) value was reported for adenoma identification.

RESULTS

Ten endoscopy experts from the United States identified conventional adenoma (vs non-adenoma) with 94.4% accuracy, 95.0% sensitivity, 93.8% specificity, 93.8% positive predictive value, and 94.9% negative predictive value using BASIC criteria. Overall strength of interobserver agreement was high: kappa 0.89 (0.82-0.96). Agreement for the individual criteria was as follows: surface mucus (93.8%), regularity (65.6%), type of pit (40.6%), pit visibility (66.9%), pit distribution (57%), vessel visibility (73%), and being lacy (46%) and peri-cryptal (61%). The confidence in diagnosis was rated at high ≥4 in 67% of the cases.

CONCLUSIONS

A group of US-based endoscopy experts have validated a simple and easily reproducible BLI classification system to characterize colorectal polyps with >90% accuracy and a high level of interobserver agreement.