ESD can be considered a standard treatment for EGC based on its expanded indications and low incidences of local recurrence and lymph node metastasis.

In recent years, due to the increasing prevalence of upper gastrointestinal endoscopy, there have been an increasing number of reports on duodenal adenoma and early stage cancer. However, endoscopic techniques for the resection of duodenal adenomas are difficult, due to the anatomical features of the duodenum, and the long distance to the lesion. There have only been a few reports on the use of endoscopic techniques for duodenal adenomas compared to those focused on the stomach and large intestine. For duodenal adenomas, we used a conventional endoscope for lesions proximal to the major duodenal papilla, and a short-type double balloon endoscope for lesions distal to the papilla. The en-bloc resection rate was 93.8%. There was only one case of microperforation. Endoscopic manipulation is considered difficult in the deep areas of the duodenum, but double balloon endoscopy enabled stable manipulation and successful resection of the tumor in the majority of cases.

Colonic mucosa-associated lymphoid tissue (MALT) lymphomas are rare and a definitive treatment has not been established. Solitary or multiple, elevated or polypoid lesions are the usual appearances of MALT lymphoma in the colon and sometimes the surface may reveal abnormal vascularity. In this paper we report our experience with four cases of colonic MALT lymphoma and review the relevant literature. The first patient had a smooth elevated lesion in the rectum and histopathologic examination of the biopsy from the lesion showed centrocyte-like cells infiltrating the lamina propria. Endoscopic ultrasonography (EUS) revealed thickening of the submucosa and muscularis propria. The patient underwent radiation therapy, and 9 months later a repeat colonoscopy showed complete resolution of the lesion. In case 2, colonoscopy showed a polyp in the cecum; the biopsy was diagnostic of MALT lymphoma. EUS detected a hypoechoic lesion confined to the mucosal layer of the colonic wall. The patient underwent endoscopic mucosal resection of the lesion and after 6 years of follow-up there was no evidence of recurrence. The third patient had a sessile elevated lesion in the sigmoid colon for which she underwent sigmoidectomy. Pathological examination of the surgical specimen was suggestive of MALT lymphoma. The last patient had a smooth elevated lesion in the rectum and magnification endoscopy showed irregular vascular pattern. The patient underwent endoscopic submucosal dissection, and biopsy examination showed the tumor to be MALT lymphoma. Although rare, awareness of MALT lymphoma of the colon is important to evaluate the patient appropriately and to plan further management.

Dabigatran causes the esophageal mucosal injury in approximately 20% of patients. Longitudinally sloughing casts in the distal esophagus are characteristic of dabigatran-induced esophagitis.

BackgroundCirculating tumor DNA (ctDNA) carries information on tumor burden. However, the mutation spectrum is different among tumors. This study was designed to examine the utility of ctDNA for monitoring tumor burden based on an individual mutation profile.MethodologyDNA was extracted from a total of 176 samples, including pre- and post-operational plasma, primary tumors, and peripheral blood mononuclear cells (PBMC), from 44 individuals with colorectal tumor who underwent curative resection of colorectal tumors, as well as nine healthy individuals. Using a panel of 50 cancer-associated genes, tumor-unique mutations were identified by comparing the single nucleotide variants (SNVs) from tumors and PBMCs with an Ion PGM sequencer. A group of the tumor-unique mutations from individual tumors were designated as individual marker mutations (MMs) to trace tumor burden by ctDNA using droplet digital PCR (ddPCR). From these experiments, three major objectives were assessed: (a) Tumor-unique mutations; (b) mutation spectrum of a tumor; and (c) changes in allele frequency of the MMs in ctDNA after curative resection of the tumor.ResultsA total of 128 gene point mutations were identified in 27 colorectal tumors. Twenty-six genes were mutated in at least 1 sample, while 14 genes were found to be mutated in only 1 sample, respectively. An average of 2.7 genes were mutated per tumor. Subsequently, 24 MMs were selected from SNVs for tumor burden monitoring. Among the MMs found by ddPCR with > 0.1% variant allele frequency in plasma DNA, 100% (8 out of 8) exhibited a decrease in post-operation ctDNA, whereas none of the 16 MMs found by ddPCR with < 0.1% variant allele frequency in plasma DNA showed a decrease.ConclusionsThis panel of 50 cancer-associated genes appeared to be sufficient to identify individual, tumor-unique, mutated ctDNA markers in cancer patients. The MMs showed the clinical utility in monitoring curatively-treated colorectal tumor burden if the allele frequency of MMs in plasma DNA is above 0.1%.