Hot snare polypectomy vs endoscopic mucosal resection using bipolar snare for intermediate size colorectal lesions:Propensity score matching

BACKGROUND Endoscopic resection(ER)with bipolar snare,in which the electric current only passes through the tissue between the device’s two electrodes,is a prominent method used to prevent perforation due to electricity potentially.ER using bipolar snare with or without submucosal injection enabled safe resection of colorectal lesions measuring 10-15 mm in an ex vivo porcine model.ER with bipolar snare is expected to have good treatment outcomes in 10-15 mm colorectal lesions,with high safety even without submucosal injection.However,no clinical reports have compared treatment outcomes with and without submucosal injection.AIM To compare the treatment outcomes of bipolar polypectomy with hot snare polypectomy(HSP)to those with endoscopic mucosal resection(EMR).METHODS In this single-centre retrospective study,we enrolled 10-15 mm nonpedunculated colorectal lesions(565 Lesions in 463 patients)diagnosed as type 2A based on the Japan Narrow-band Imaging Expert Team classification,resected by either HSP or EMR between January 2018 and June 2021 at the National Cancer Center Hospital East.Lesions were divided into HSP and EMR groups,and propensity score matching was performed.In the matched cohort,en bloc and R0 resection rates and adverse events were compared between the two groups.RESULTS Of the 565 lesions in 463 patients,117 lesions each in the HSP and EMR groups were selected after propensity score matching.In the original cohort,there was a significant difference in antithrombotic drug use(P<0.05),lesion size(P<0.01),location(P<0.01),and macroscopic type(P<0.05)between the HSP and EMR groups.In the matched cohort,the en bloc resection rates were comparable between both groups[93.2%(109/117)vs 92.3%(108/117),P=0.81],and there was no significant difference in the R0 resection rate[77.8%(91/117)vs 80.3%(94/117),P=0.64].The incidence of delayed bleeding was similar in both groups[1.7%(2/117)].Perforation occurred in the EMR group[0.9%(1/117)]but not in the HSP group.CONCLUSION Using bipolar snare,ER of nonpedunculated 10-15 mm colorectal lesions may be performed safely and effectively,even without submucosal injection.

Narrow-band imaging optical chromocolonoscopy: Advantages and limitations

Narrow-band imaging (NBI) is an innovative optical technology that modifies the center wavelength and bandwidth of an endoscope’s light into narrow-band illumination of 415 ± 30 nm. NBI markedly improves capillary pattern contrast and is an in vivo method for visualizing microvessel morphological changes in superficial neoplastic lesions. The scientific basis for NBI is that short wavelength light falls within the hemoglobin absorption band, thereby facilitating clearer visualization of vascular structures. Several studies have reported advantages and limitations of NBI colonoscopy in the colorectum. One difficulty in evaluating results, however, has been non-standardization of NBI systems (Sequential and non-sequential). Utilization of NBI technology has been increasing worldwide, but accurate pit pattern analysis and suffi cient skill in magnifying colonoscopy are basic fundamentals required for profi ciency in NBI diagnosis of colorectal lesions. Modern optical technology without proper image interpretation wastes resources, confuses untrained endoscopists and delays inter-institutional validation studies. Training in the principles of "optical image-enhanced endoscopy" is needed to close the gap between technological advancements and their clinical usefulness. Currently available evidence indicates that NBI constitutes an effective and reliable alternative to chromocolonoscopy forin vivo visualization of vascular structures, but further study assessing reproducibility and effectiveness in the colorectum is ongoing at various medical centers.

Risk factors for intraoperative perforation during endoscopic submucosal dissection of superficial esophageal squamous cell carcinoma

AIM To identify the risk factors and clarify the subsequent clinical courses.METHODS This study retrospectively analyzed consecutive patients with esophageal squamous cell carcinoma( ESCC) treated using endoscopic submucosal dissection(ESD) between April 2008 and October 2012. We divided the ESCC lesions into perforation cases and non-perforation cases, and compared characteristics and endoscopic findings between the two groups. "Intraoperative perforation" was defined as the detection of a perforation site during ESD and the presence of mediastinal emphysema.RESULTS In total, 147 patients with 156 ESCC lesions were treated by ESD. Intraoperative perforation was recorded for nine lesions(5.8%) from nine patients. Multivariate analysis identified mucosal deficiency larger than 75% of the circumference of the esophagus as an independent risk factor for intraoperative perforation(OR = 7.37, 95%CI: 1.45-37.4, P = 0.016). The predominant site of perforation was the left wall [6/9(67%)]. Six of nine perforation sites were successfully closed by clips during the procedures. Two of nine cases required drainage for pleural effusions; however, all nine cases recovered with conservative treatment and without surgical intervention. At the median follow up of 42 mo after ESD, no cases of local recurrence or distant organ metastasis had been observed.CONCLUSION This study suggests that mucosal deficiency larger than 75% of the luminal circumference is a risk factor for intraoperative perforation during ESD for ESCC.

Clinical impact of surveillance for head and neck cancer in patients with esophageal squamous cell carcinoma

AIM To evaluate the clinical impact of surveillance for head and neck(HN) region with narrow band imaging(NBI) in patients with esophageal squamous cell carcinoma(ESCC).METHODS Since 2006, we introduced the surveillance for HN region using NBI for all patients with ESCC beforetreatment, and each follow-up. The patients with newly diagnosed stage Ⅰ to Ⅲ ESCC were enrolled and classified into two groups as follows: Group A(no surveillance for HN region); between 1992 and 2000), and Group B (surveillance for HN region with NBI; between 2006 and 2008). We comparatively evaluated the detection rate of superficial head and neck squamous cell carcinoma (HNSCC), and the serious events due to metachronous advanced HNSCC during the follow-up.RESULTS A total 561 patients(group A: 254, group B: 307) were enrolled. Synchronous superficial HNSCC was detected in 1 patient (0.3%) in group A, and in 12 (3.9%) in group B (P=0.008). During the follow up period, metachronous HNSCC were detected in 10 patients(3.9%) in group A and in 30 patients(9.8%) in group B(P = 0.008). All metachronous lesions in group B were early stage, and 26 patients underwent local resection, however, 6 of 10 patients (60%) in group A lost their laryngeal function and died with metachronous HNSCC.CONCLUSION Surveillance for the HN region by using NBI endoscopy increase the detection rate of early HNSCC in patients with ESCC, and led to decrease serious events related to advanced metachronous HNSCC.

Size does not determine the grade of malignancy of early invasive colorectal cancer

AIM:To clarify the clinicopathological characteristics of small and large early invasive colorectal cancers(EI-CRCs),and to determine whether malignancy grade depends on size.METHODS:A total of 583 consecutive EI-CRCs treated by endoscopic mucosal resection or surgery at the National Cancer Center Hospital between 1980 and 2004 were enrolled in this study.Lesions were classified into two groups based on size:small(≤10mm) and large(>10mm).Clinicopathological features,incidence of lymph node metastasis(LNM) and risk factors for LNM,such as depth of invasion,lymphovascular invasion(LVI) and poorly differentiated adenocarcinoma(PDA) were analyzed in all resected specimens.RESULTS:There were 120(21%) small and 463(79%) large lesions.Histopathological analysis of the small lesion group revealed submucosal deep cancer(sm:≥1000 μm) in 90(75%) cases,LVI in 26(22%) cases,and PDA in 12(10%) cases.Similarly,the large lesion group exhibited submucosal deep cancer in 380(82%) cases,LVI in 125(27%) cases,and PDA in 79(17%) cases.The rate of LNM was 11.2% and 12.1% in the small and large lesion groups,respectively.CONCLUSION:Small EI-CRC demonstrated the same aggressiveness and malignant potential as large cancer.

Alpha-fetoprotein-producing colon cancer with atypical bulky lymph node metastasis

Alpha-fetoprotein (AFP)-producing colorectal cancer is extremely rarely reported until now. All of the reported cases harboring synchronous hematogenous spread including liver and/or lung metastasis had a poor prognosis and died within 12 mo. We here describe a 71-year old man with AFP-producing colon cancer who presented with an unusual bulky lymph node metastasis instead of hematogenous spread. He underwent adjuvant chemotherapy in addition to curative surgical resection, which prolonged his survival.

Unexpected endoscopic full-thickness resection of a duodenal neuroendocrine tumor

A 57-year-old man underwent endoscopy for investigation of a duodenal polyp. Endoscopy revealed a hemispheric submucosal tumor, about 5 mm in diameter, in the anterior wall of the duodenal bulb. Endoscopic biopsy disclosed a neuroendocrine tumor histologically, therefore endoscopic mucosal resection was conducted. The tumor was effectively and evenly elevated after injection of a mixture of 0.2% hyaluronic acid and glycerol at a ratio of 1:1 into the submucosal layer. A small amount of indigo-carmine dye was also added for coloration of injection fluid. The lesion was completely resected en bloc with a snare after submucosal fluid injection. Immediately, muscle-fiber-like tissues were identified in the marginal area of the resected defect above the blue-colored layer, which suggested perforation. The defect was completely closed with a total of 9 endoclips, and no symptoms associated with peritonitis appeared thereafter. Histologically, the horizontal and vertical margins of the resected specimen were free of tumor and muscularis propria was also seen in the resected specimen. Generally, endoscopic mucosal resection is considered to be theoretically successful if the mucosal defect is colored blue. The blue layer in this case, however, had been created by unplanned injection into the subserosal rather than the submucosal layer.

A laterally-spreading tumor in a colonic interposition treated by endoscopic submucosal dissection

Herein we describe an early colonic carcinoma which developed in a colonic interposition 14 years after surgery for esophageal cancer, which was successfully treated by endoscopic submucosal dissection (ESD). An 80-year-old man underwent colonic interposition between the upper esophagus and stomach after surgery for an early esophageal squamous cell carcinoma in 1994. He received a surveillance endoscopy, and a laterally-spreading tumor of granular type, approximately 20 mm in size, was identified in the colonic interposition. An endoscopic biopsy revealed moderately differentiated adenocarcinoma histologically, however, we diagnosed the lesion as an intramucosal carcinoma based on the endoscopic findings. The lesion was safely and completely removed en bloc by ESD using a bipolar knife. Histologically, the lesion was an intramucosal moderately differentiated adenocarcinoma in a tubular adenoma.