Publications by authors named "Koichi Hamada"

Background: Gastric foveolar type neoplasia is a rare histological variant of gastric tumors. It is very difficult to differentiate between benign and malignant intraepithelial foveolar neoplasia (IFN). Although limited molecular alterations have been identified in IFNs, somatic copy number alterations (SCNAs), which are linked to tumor progression, have not been systematically evaluated in IFN.

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Article Synopsis
  • Esophageal cancers that penetrate the muscularis mucosa or submucosa can have a risk of lymph node metastasis after endoscopic resection, but the patterns of metastatic recurrence post-treatment are not well-studied.
  • Researchers analyzed data from 220 patients in Japan who received additional treatments (esophagectomy, chemoradiotherapy, or radiation) after endoscopic resection between 2006 and 2017 to identify risk factors for metastatic recurrence.
  • They found that lymphatic invasion is a key risk factor for recurrence, and while both esophagectomy and chemoradiotherapy show similar risks for metastasis, esophagectomy tends to have higher locoregional recurrence but better survival rates for patients who do experience
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Background: The present study aimed to evaluate proton beam therapy (PBT) for stage IV pancreatic adenocarcinoma and its metastases and define the criteria for eligibility. Materials and methods: We retrospectively evaluated the patients who had a histopathological diagnosis of pancreatic adenocarcinoma, had progressed to stage IV, and underwent PBT for both the primary and some metastatic lesions between 2017 and 2022. PBT was performed using the passive scattering technique.

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Here, we report a rare case of a depressed lesion exhibiting both tubular differentiated adenocarcinomatous (TDA) and intraepithelial foveolar neoplasia (IFN) components (with the histological appearance of foveolar hyperplasia due to low-grade atypia). Histologically, the TDA surrounded the IFN, suggesting that the TDA may have originated from the IFN. Therefore, we examined molecular alterations in the TDA and IFN components separately.

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Background: Takotsubo cardiomyopathy (TC) is a well-known complication of subarachnoid haemorrhage (SAH), often accompanied by neurogenic myocardial dysfunction. Although TC has been reported to be associated with higher morbidity and mortality among patients with aneurysmal SAH (aSAH), some patients have been reported to recover, the profiles and follow-up outcomes of these survivors remain unclear.

Materials And Methods: To characterize the profiles of patients with aSAH complicated by TC who experienced favourable outcomes using long-term follow-up data, a consecutive series of patients with aSAH were enrolled and TC diagnosis was based on the revised version of the Mayo Clinic criteria.

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Esophageal squamous cell carcinoma (SCC) with dark spots caused by melanocytosis is very rare. A reddish and flat lesion, 4 cm in length and covering over two-thirds of the circumference, was found in the midthoracic esophagus of a 66-year-old male. Multiple brown and black spots are observed in the lesion.

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Background And Aims: Data regarding the status of the vertical margin of sessile serrated lesions (SSLs) resected using cold snare polypectomy (CSP) are lacking, and whether a histopathologically positive vertical margin is related to recurrence remains unclear. Therefore, this preliminary study aimed to clarify the rates of positive or unassessable vertical and horizontal margins and the rate of muscularis mucosae resection in SSLs treated using CSP compared with those treated with EMR.

Methods: Histologic outcomes of patients treated with CSP or EMR for SSLs were evaluated in this single-center observational study.

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Local treatment of oligometastatic esophagogastric cancer has been reported to improve overall survival (OS) compared to systemic therapy alone. This study evaluated the feasibility and safety of proton beam therapy (PBT) for the treatment of lung oligometastatic recurrence in esophageal cancer patients. This single-center historical cohort study enrolled 11 patients who underwent PBT for lung oligometastasis from esophageal cancer between 2010 and 2019.

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In bioengineering, fluorescent amine-reactive probes are invaluable for the detection of amine species. In particular, targeting probes for lysine, which has a free amino group in amino acids, are a valid method for protein detection. For this purpose, many fluorescent "turn-on type" probes with amine reactivity have been developed; however, they require improvements.

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A 74-year-old man was admitted to our hospital with severe hematochezia. Abdominal enhanced computed tomography (CT) demonstrated extravasation of contrast material from the descending colon. Colonoscopy revealed recent bleeding in the descending colon diverticulum.

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There are several reports of hepatic resection for postoperative hepatic metastatic recurrence of esophageal cancer. However, it is unclear whether surgery is the best local treatment for liver metastases. Thus, this study aimed to retrospectively analyze proton beam therapy (PBT) for postoperative liver metastatic recurrence of esophageal cancer without extrahepatic lesions and examine outcomes and adverse events.

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We report a case of a 70-year-old male with delayed perforation in the cecum treated by endoscopic ultrasonography-guided drainage for a pelvic abscess. The lesion was a 50-mm laterally spreading tumor, and endoscopic submucosal dissection (ESD) was performed. No perforation was detected during the operation, and en bloc resection was achieved.

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Background: The guidelines recommend additional gastrectomy after noncurative endoscopic resection for early gastric cancers (EGCs). However, no additional treatment might be acceptable in some patients aged ≥ 85 years. We aimed to identify this patient group using the data in a highly aged area.

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Article Synopsis
  • A 62-year-old woman with a small (6.3-mm) low-grade neuroendocrine tumor of the ampulla of Vater successfully underwent an endoscopic papillectomy.
  • The procedure was complication-free, and during a follow-up period of 26 months, she showed no signs of local recurrence or metastasis.
  • While the treatment of ampullary neuroendocrine tumors is debated, endoscopic papillectomy may be a viable option for tumors that are small, low-grade, and lack invasion into surrounding tissues.
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Background And Purpose: There are no existing reports on proton beam therapy (PBT) for local control (LC) of liver metastasis of colorectal cancer (LMCRC). We calculated the LC rate of PBT for LMCRC and explored the influence of each factor on the LC rate.

Materials And Methods: Cases in which PBT was performed at our center between 2009 and 2018 were retrospectively selected from the database.

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Background: Although additional treatment is considered for patients with esophageal squamous cell carcinoma (ESCC) invading into the muscularis mucosa (pT1a-MM) or submucosa (pT1b-SM) after endoscopic submucosal dissection (ESD), the actual benefits of this method remain to be elucidated.

Aims: We aimed to evaluate the prognostic benefits of additional treatment in such patients.

Methods: Between 2006 and 2017, we enrolled patients with pT1a-MM/pT1b-SM ESCC after ESD at 21 institutions in Japan.

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Background/aim: This study aimed to examine the effectiveness of polypectomy with cutting current (PCC) for colorectal polyps, compared with cold snare polypectomy (CSP).

Patients And Methods: The study design was a singlecenter randomized controlled trial. We included patients with one or more non-pedunculated colorectal polyps of 6 mm or more and less than 10 mm.

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Objectives: We aimed to clarify the prognostic factors for patients with esophageal squamous cell carcinoma (ESCC) invading into the muscularis mucosa (pT1a-MM) or submucosa (pT1b-SM) after endoscopic submucosal dissection (ESD).

Methods: This retrospective study enrolled such patients at 21 institutions in Japan between 2006 and 2017. We evaluated 15 factors, including pathological risk categories for ESCC-specific mortality, six non-cancer-related indices, and treatment strategies.

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Background: The clipping method is widely used in endoscopic hemostasis for colonic diverticular hemorrhage. Recently, rebleeding was shown to be less common in ligation therapy than in clipping. Ligation methods include endoscopic band ligation (EBL) and endoscopic detachable snare ligation (EDSL).

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