Post-polypectomy surveillance: the present and the future

An appropriate post-polypectomy surveillance program requires the effectiveness of reducing colorectal cancer and safety. In addition, the post-polypectomy surveillance program should consider the burden of limited medical resource capacity, cost-effectiveness, and patient adherence. In this sense, a risk-stratified surveillance program based on baseline colonoscopy results is ideal. Major international guidelines for post-polypectomy surveillance, such as those from the European Union and the United States, have recommended risk-stratified surveillance programs. Both guidelines have recently been updated to better differentiate between high- and low-risk individuals. In both updated guidelines, more individuals have been downgraded to lower-risk groups that require less frequent or no surveillance. Furthermore, increased attention has been paid to the surveillance of patients who undergo serrated polyp removal. Previous guidelines in Japan did not clearly outline the risk stratification in post-polypectomy surveillance. However, the new colonoscopy screening and surveillance guidelines presented by the Japan Gastroenterological Endoscopy Society include a risk-stratified post-polypectomy surveillance program. Further discussion and analysis of unresolved issues in this field, such as the optimal follow-up after the first surveillance, the upper age limit for surveillance, and the ideal method for improving adherence to surveillance guidelines, are warranted

Cost-Effectiveness of Total Colonoscopy in Screening of Colorectal Cancer in Japan

Introduction. In Japan, the cost-effectiveness of total colonoscopy (TCS) for primary screening of colorectal cancer (CRC) is unclear. We compared the cost of identifying a patient with CRC using two primary screening strategies: TCS (strategy 1) and the immunochemical fecal test (FIT) (strategy 2). Materials and Methods. We retrospectively analyzed the TCS screening database at our institution from February 2004 to August 2010 (strategy 1, n = 15,348) and the Japanese nationwide survey of CRC screening in 2008 (strategy 2, n = 5,267,443). Results. 112 and 6,838 CRC cases were detected in strategies 1 and 2, costing 2,124,000 JPY and 1,629,000 JPY, respectively. The rate of earlier-stage CRC was higher in strategy 1. Conclusions. The cost was higher using TCS as a primary screening procedure. However, the difference was not excessive, and considering the increased rate of detecting earlier CRC, the use of TCS as a primary screening tool may be cost-effective

Colonoscopy quality and endoscopist factors: what are the required endoscopist conditions for high-quality colonoscopy to reduce colorectal cancer incidence and mortality?

To maximize the effectiveness of colonoscopy in decreasing the incidence and mortality of colorectal cancer (CRC), high-quality colonoscopy procedures are essential. Considering that the colonoscopy quality varies among endoscopists, it is important to understand the endoscopist factors that influence the colonoscopy quality. In this paper, we reviewed the endoscopist factors related to colonoscopy quality. There are several quality indicators of colonoscopy, among which the adenoma detection rate is the most established indicator with evidence of its correlation with post-colonoscopy CRC. With respect to lesion detectability during colonoscopy, there are other measurements such as the sessile serrated lesion detection rate; however, further evidence on their relationships with post-colonoscopy CRC is needed. Previous studies that have examined the endoscopist characteristics influencing colonoscopy quality have suggested that several factors, including experience, the volume of colonoscopy procedures, and endoscopist specialty, are related to lesion detectability. However, discrepancies exist regarding the studies’ results; in particular, the influence of endoscopist specialty on coloscopy quality is controversial. Some recent studies have demonstrated that endoscopist specialty is not related to lesion detectability when considering confounding factors. Furthermore, it has been reported that nurse endoscopists can provide high-quality colonoscopy after training. It may be possible for endoscopists to improve their colonoscopy quality, regardless of specialty. Training, monitoring, and feedback of colonoscopy quality measurements are useful interventions for endoscopists to ensure high-quality procedures. Owing to the continuous development of endoscopic technologies, it is believed that training is useful for both inexperienced and experienced endoscopists

Mo1671 a decision-tree classifier to improve the accuracy of magnification endoscopic assessment of lateral spreading tumours

Introduction: it is well known that when performing endoscopy for depth diagnosis of T1 colorectal cancer (CRC) one sometimes experiences, the difficulty of depth diagnosis, even with magnification. This is especially the case in lesions containing large nodules. It has been reported that the location of submucosal invasion in laterally spreading tumors (LST) varies between granular type (G) and non-granular type (NG).We hypothesize that the contribution of pit pattern diagnosis and JNET classification using magnified endoscopy is different between LST-G and LST-NG.Methods: a total of 647 LSTs in 612 patients with diagnosed tumor in-situ (Tis) or T1 diagnosed by magnified endoscopy using both pit-pattern and JNET classification were analyzed retrospectively.All lesions were either endoscopically or surgically resected at our institution between Jan 2015 and Dec 2017. All endoscopic findings were recorded in the “Japan Endoscopic Database (JED)”. Independent variables included: JNET classification, macroscopic features, endoscopically estimated lesion size for lesions T1b or deeper. The lesions were divided into LST-G or LST-NG. Histological diagnosis was used as the gold standard for assessing the depth of invasion.The lesions were randomly split 50-50 into test and training datasets and a decision tree classifier was trained on each group using the training data. Then the model was deployed on the test set and a receiver operator curve (ROC) was calculated for each model’s performance on the test set.Results: among all the LSTs, mean size of the lesions were 27.5mm. The ratio of macroscopic features was as follows;The number of LST-G’s was 369 and LST-NG’s 278.Lesions of T1b or deeper were included 91 (24.7%) and 76 (37.3%).The AUC of ROC for LST-G’s was 0.892 in the training data set and 0.846 in the test data set. The weighted variable contribution to the algorithm for the diagnosis of T1b or deeper was as follows; Pit pattern: 0.74, JNET: 0.19, macroscopic features: 0.08, and size of the lesion: 0.0.On the other hand, The AUC for LST-NG’s was 0.931 in the training data set and 0.938 in the validation data set. The variable contribution was as follows; Pit pattern: 0.92, JNET: 0.05, size: 0.02 and macroscopic features: 0.0.The decision tree of LST-NG, a combination of endoscopic findings showed 73% to 96% sensitivity for T1b or deeper and 84% to 98% specificity.LST-G demonstrated 86% sensitivity and 54% to 95% specificity. The specificity was lowest for 0-Is or 0-Is+IIc lesions.Conclusion: pit patterns contributed to the diagnosis of T1b or deeper in both LST-G and LST-NG models. In the case of LST-G with 0-Is component, it appears that depth diagnosis difficult regardless of the size of the lesions. Further research is warranted in this area in order to improve things further

Metachronous Gastric Cancer Following Curative Endoscopic Resection of Early Gastric Cancer

This review article summarizes knowledge about metachronous gastric cancer (MGC) occurring after curative endoscopic resection (ER) of early gastric cancer (EGC), treatment outcomes of patients who developed MGC, and efficacy of Helicobacter pylori eradication to prevent MGC. The incidence of MGC following curative ER increases over time and is higher than in patients undergoing gastrectomy. Increasing age and multifocal EGC are independent risk factors for developing MGC. An MGC following curative ER is usually a small (<20 mm) and differentiated intramucosal cancer. Most MGC lesions are found at an early stage on semiannual or annual surveillance endoscopy and are successfully treated by further ER, with excellent long-term outcomes. Eradication of H. pylori may reduce the risk of MGC following ER of EGC, but further prospective studies with long-term outcomes are required. Surveillance endoscopy following gastric ER should be continued indefinitely, due to the risk of MGC even after successful H. pylori eradication. Risk stratification and tailored endoscopic surveillance schedules need to be developed

Conditional inference tree models to perceive depth of invasion in T1 colorectal cancer

Background and aim: accurate diagnosis of invasion depth for T1 colorectal cancer is of critical importance as it decides optimal resection technique. Few reports have previously covered the effects of endoscopic morphology on depth assessment. We developed and validated a novel diagnostic algorithm that accurately predicts the depth of early colorectal cancer.Methods: we examined large pathological and endoscopic databases compiled between Jan 2015 and Dec 2018. Training and validation data cohorts were derived and real-world diagnostic performance of two conditional interference tree algorithms (Models 1 and 2) was evaluated against that of the Japan NBI-Expert Team (JNET) classification used by both expert and non-expert endoscopists.Results: model 1 had higher sensitivity in deep submucosal invasion than that of JNET alone in both training (45.1% vs. 28.6%, p &lt; 0.01) and validation sets (52.3% vs. 40.0%, p &lt; 0.01). Model 2 demonstrated higher sensitivity than Model 1 (66.2% vs. 52.3%, p &lt; 0.01) in excluding deeper invasion of suspected Tis/T1a lesions.Conclusion: we discovered that machine-learning classifiers, including JNET and macroscopic features, provide the best non-invasive screen to exclude deeper invasion for suspected Tis/T1 lesions. Adding this algorithm improves depth diagnosis of T1 colorectal lesions for both expert and non-expert endoscopists

Cost‐effectiveness of preventive aspirin use and intensive downstaging polypectomy in patients with familial adenomatous polyposis: A microsimulation modeling study

Abstract Objective Although there is increasing evidence to suggest the cost‐effectiveness of aspirin use to prevent colorectal cancer (CRC) in the general population, no study has assessed cost‐effectiveness in patients with familial adenomatous polyposis (FAP), who are at high risk of developing CRC. We examined the cost‐effectiveness of preventive use of low‐dose aspirin in FAP patients who had undergone polypectomy in comparison with current treatment practice. Design We developed a microsimulation model that simulates a hypothetical cohort of the Japanese population with FAP for 40 years. Three scenarios were created based on three intervention strategies for comparison with no intervention, namely intensive downstaging polypectomy (IDP) of colorectal polyps at least 5.0 mm in diameter, IDP combined with low‐dose aspirin, and total proctocolectomy with ileal pouch‐anal anastomosis (IPAA). Cost‐effective strategies were identified using a willingness‐to‐pay threshold of USD 50,000 per QALY gained. Results Compared with no intervention, all strategies resulted in extended QALYs (21.01–21.43 QALYs per individual) and showed considerably reduced colorectal cancer mortality (23.35–53.62 CRC deaths per 1000 individuals). Based on the willingness‐to‐pay threshold, IDP with low‐dose aspirin was more cost‐effective than the other strategies, with an incremental cost‐effectiveness ratio of $57 compared with no preventive intervention. These findings were confirmed in both one‐way sensitivity analyses and probabilistic sensitivity analyses. Conclusion This study suggests that the strategy of low‐dose aspirin with IDP may be cost‐effective compared with IDP‐only or IPAA under the national fee schedule of Japan