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Dive into the research topics where Hiroyuki Isayama is active.

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Featured researches published by Hiroyuki Isayama.


Surgical Endoscopy and Other Interventional Techniques | 2018

Self-expandable metallic stenting as a bridge to surgery for malignant colorectal obstruction: pooled analysis of 426 patients from two prospective multicenter series

Masafumi Tomita; Shuji Saito; Shinichiro Makimoto; Shuntaro Yoshida; Hiroyuki Isayama; Tomonori Yamada; Takeaki Matsuzawa; Toshiyuki Enomoto; Rika Kyo; Toshio Kuwai; Nobuto Hirata; Mamoru Shimada; Tomio Hirakawa; Koichi Koizumi; Yoshihisa Saida

BackgroundSelf-expandable metallic stenting (SEMS) for malignant colorectal obstruction (MCO) as a bridge to elective surgery (BTS) is a widely used procedure. The aim of this study was to assess short-term outcomes of SEMS for MCO as BTS.MethodsThis study analyzed pooled data from BTS patients who were enrolled in two multicenter prospective single-arm observational clinical studies that used different stent types. Both studies were conducted by the Japan Colonic Stent Safe Procedure Research Group (JCSSPRG). The first study evaluated the WallFlex™ colonic stent for BTS or palliative treatment (PAL) from May 2012 to October 2013 and the second evaluated the Niti-S™ colonic stent from October 2013 to May 2014. Fifty-three facilities in Japan participated in the studies. Before each study started, the procedure had been shared with the participating institutions by posting details of the standard methods of SEMS placement on the JCSSPRG website. Patients were followed until discharged after surgery.ResultsA total of 723 consecutive patients were enrolled in the two studies. After excluding nine patients, the remaining 714 patients were evaluated as a per-protocol cohort. SEMS placement was performed in 426 patients (312 WallFlex and 114 Niti-S) as BTS and in 288 as PAL. In the 426 BTS patients, the technical success rate was 98.1% (418/426). The clinical success rate was 93.8% (392/418). SEMS-related preoperative complications occurred in 8.5% of patients (36/426), perforations in 1.9% (8/426), and stent migration in 1.2% (5/426). Primary anastomosis was possible in 91.8% of patients (391/426), 3.8% of whom (15/393) had anastomosis leakage. The overall stoma creation rate was 10.6% (45/426). The postoperative complication rate was 16.9% (72/426) and mortality rate was 0.5% (2/426).ConclusionsSEMS placement for MCO as BTS is safe and effective with respect to peri-procedural outcomes. Further investigations are needed to confirm long-term oncological outcomes.


Journal of Gastroenterology | 2018

Clinical guidelines for primary sclerosing cholangitis 2017

Hiroyuki Isayama; Susumu Tazuma; Norihiro Kokudo; Atsushi Tanaka; Toshio Tsuyuguchi; Takahiro Nakazawa; Kenji Notohara; Suguru Mizuno; Nobuhisa Akamatsu; Masahiro Serikawa; Itaru Naitoh; Yoshiki Hirooka; Toshifumi Wakai; Takao Itoi; Tomoki Ebata; Shinji Okaniwa; Terumi Kamisawa; Hiroki Kawashima; Atsushi Kanno; Keiichi Kubota; Masami Tabata; Michiaki Unno; Hajime Takikawa

BackgroundPrimary sclerosing cholangitis (PSC) is relatively rare disease and pathogenesis and methods of treatments were still not established. Then, we had conducted the making clinical guidelines to manage patients with PSC based on the literature review and expert opinions. These clinical guidelines were made for the medical doctors on the management of PSC, except child case of PSC.MethodsWe had employed modified Delphi method. The production committee decided guidelines, strength of recommendations and evidence level after reviewed literatures systematically, and The Expert panel evaluated those. The Scientific Committee of the Japan Biliary Association (JBA) evaluated revised guidelines, and the Public comments were collected on web site of JBA.ResultsWe had made 16 guidelines about epidemiology/pathophysiology, diagnostics, therapy and prognosis. Also, we had made both diagnostic and therapeutic flow chart.ConclusionsWe hope that these guidelines will contribute to the improvement and development of the medical care of PSC.


International Journal of Obesity | 2018

Visceral adiposity and high adiponectin levels are associated with the prevalence of pancreatic cystic lesions

Suguru Mizuno; Yousuke Nakai; Hiroyuki Isayama; Takeharu Yoshikawa; Kei Saito; Naminatsu Takahara; Hirofumi Kogure; Minoru Tada; Naoto Hayashi; Kazuhiko Koike

ObjectivesObesity is increasing in developed countries and is a risk factor for pancreatic cancer (PaC). We previously reported that obesity was associated with pancreatic cystic lesions (PCLs), which are both precursors of, and risk factors for, PaC. In the present study, we further investigated the relationship between visceral adiposity and adiponectin levels and the extent of PCLs.MethodsIndividuals who underwent comprehensive health screening at our institution between January 2008 and March 2013 were analyzed. PCLs were diagnosed via magnetic resonance imaging using a 3.0 Tesla system. The volumes of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were measured from computed tomographic volume data. Serum levels of adiponectin were measured using a sandwich enzyme-linked immunosorbent assay.ResultsThe prevalences of PCLs were 14.2% in males (N = 2683; mean age, 56.4 years) and 16.2% in females (N = 1741; mean age, 57.1 years). The prevalence of PCLs increased gradually as VAT volume increased (P < 0.001). PCLs were more prevalent in individuals with high adiponectin levels (18.7% vs. 13.8%, P = 0.005). VAT volume (odds ratio [OR] for the highest quartiles, 1.52 [1.07–2.16]; P = 0.025) and adiponectin level (OR for the highest quartiles, 1.31 [1.08–1.59]; P = 0.007) but not SAT volume (P = 0.828) was significantly associated with PCLs in multivariate analyses.ConclusionsVisceral adiposity and high adiponectin levels were associated with PCL prevalence. Further work is needed to explore the relationships between visceral adiposity and adiponectin levels, and PCLs and PaC.


Digestive Endoscopy | 2018

Factors related to difficult self-expandable metallic stent placement for malignant colonic obstruction: A post-hoc analysis of a multicenter study across Japan

Toshio Kuwai; Toshiki Yamaguchi; Hiroki Imagawa; Shuntaro Yoshida; Hiroyuki Isayama; Takeaki Matsuzawa; Tomonori Yamada; Shuji Saito; Mamoru Shimada; Nobuto Hirata; Takashi Sasaki; Koichi Koizumi; Iruru Maetani; Yoshihisa Saida

Colorectal cancer patients often present with large bowel obstruction. Elective placement of a self‐expandable metallic stent (SEMS) can relieve obstruction, but can be challenging. Previous studies have compared cases by outcomes only, but the present study investigated successful cases only to identify factors related to prolonged and difficult SEMS placement in patients with malignant colonic obstruction.


Archive | 2018

Endoscopic Treatment of Adenomas of the Ampulla of Vater: Techniques, Results, Benefits, and Limitations

Natsuyo Yamamoto; Hiroyuki Isayama; Kazuhiko Koike


Journal of Gastroenterology | 2018

A proposed severity classification system for hepatolithiasis based on an analysis of prognostic factors in a Japanese patient cohort.

Yutaka Suzuki; Toshiyuki Mori; Masaaki Yokoyama; Sangchul Kim; Hirokazu Momose; Ryota Matsuki; Masaharu Kogure; Nobutsugu Abe; Hiroyuki Isayama; Takahiro Nakazawa; Kenji Notohara; Atsushi Tanaka; Toshio Tsuyuguchi; Susumu Tazuma; Hajime Takikawa; Masanori Sugiyama


Gastrointestinal intervention | 2018

Greetings from the Guest Editor

Hiroyuki Isayama


Gastrointestinal intervention | 2018

Usefulness of stent placement above the papilla, so-called, ‘inside stent’

Tanyaporn Chantarojanasiri; Hirofumi Kogure; Tsuyoshi Hamada; Yousuke Nakai; Hiroyuki Isayama


Gastrointestinal intervention | 2018

TOKYO criteria: Standardized reporting system for endoscopic biliary stent placement

Tsuyoshi Hamada; Yousuke Nakai; Hiroyuki Isayama


Annals of Oncology | 2018

737PA phase II trial of gemcitabine, S-1 and LV combination therapy in patients with advanced pancreatic cancer

Kei Saito; Y. Nakai; Hiroyuki Isayama; Kazunaga Ishigaki; Tomotaka Saito; Naminatsu Takahara; Suguru Mizuno; Hirofumi Kogure; Kazuhiko Koike

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Naoki Sasahira

Japanese Foundation for Cancer Research

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Yousuke Nakai

University of California

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Osamu Togawa

Saitama Medical University

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Kenji Hirano

Memorial Hospital of South Bend

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