Toru Hiyama

Hiroshima University, Hirosima, Hiroshima, Japan

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Publications (104)397.4 Total impact

  • Gastrointestinal Endoscopy 05/2015; 81(5):AB467. DOI:10.1016/j.gie.2015.03.1676 · 4.90 Impact Factor
  • Gastroenterology 04/2015; 148(4):S-919. DOI:10.1016/S0016-5085(15)33121-8 · 13.93 Impact Factor
  • Helicobacter 02/2015; 20(2). DOI:10.1111/hel.12210 · 2.99 Impact Factor
  • Toru Hiyama, Masaharu Yoshihara
    Scandinavian Journal of Gastroenterology 01/2015; 50(5):1-2. DOI:10.3109/00365521.2015.1008036 · 2.33 Impact Factor
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    ABSTRACT: Background The incidence of early-onset (under 50 years of age) colorectal cancer (CRC) in the Vietnamese has been reported to be quite higher than that in the Japanese. To clarify the differences in genetic alterations between Vietnamese and Japanese CRCs, we investigated mutations in K-ras and mitochondrial DNA (mtDNA) and high-frequency microsatellite instability (MSI-H) in the CRCs of Vietnamese and Japanese patients.Methods We enrolled 60 Vietnamese and 233 Japanese patients with invasive CRCs. DNA was extracted from formalin-fixed, paraffin-embedded tissue sections. K-ras mutations were examined with PCR-single-strand conformation polymorphism analysis. mtDNA mutations and MSI-H were examined with microsatellite analysis using D310 and BAT-26, respectively.ResultsK-ras mutations were examined in 60 Vietnamese and 45 Japanese CRCs. The frequency of the mutations in the Vietnamese CRCs was significantly higher than that in the Japanese CRCs (8 of 24 [33%] vs 5 of 45 [11%], p =0.048). MSI-H was examined in 60 Vietnamese and 130 Japanese CRCs. The frequency of MSI-H in the Vietnamese CRCs was also significantly higher than that in the Japanese CRCs (6 of 27 [22%] vs 10 of 130 [8%], p =0.030). mtDNA mutations were examined in 60 Vietnamese and 138 Japanese CRCs. The frequency of mtDNA mutations in the Vietnamese CRCs was significantly higher than that in the Japanese CRCs (19 of 44 [43%] vs 11 of 133 [9%], p <0.001). There were no significant differences in clinicopathologic characteristics, such as age, sex, tumour location, and depth, in terms of tumours with/without each genetic alteration in the CRCs of the Vietnamese and Japanese patients.Conclusions These results indicate that the developmental pathways of CRCs in the Vietnamese may differ from those of CRCs in the Japanese.
    BMC Gastroenterology 11/2014; 14(1):203. DOI:10.1186/s12876-014-0203-0 · 2.11 Impact Factor
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    ABSTRACT: To assess the value of a new test for the diagnosis of Helicobacter pylori (H. pylori) infection, Rapirun(®) H. pylori Antibody Stick (Rapirun(®) Stick), in a Vietnamese population. Eligible patients without previous history of H. pylori eradication were recruited. Rapid urease test (RUT) and histologic examination were used to diagnose the H. pylori infection. Patients were considered H. pylori positive when the RUT results were positive and/or the bacteria were detected histologically. Rapirun(®) Stick tests were performed using urine samples, and the results were compared with the other 2 methods. We enrolled 200 patients with a mean age of 36 (range, 18-76) years. There were 116 females and 84 males. Of the 200 patients, 111 (55.5%) were diagnosed as being H. pylori positive. The sensitivity, specificity, and accuracy of the Stick test were 84.7%, 89.9%, and 87.0%, respectively. There were 17 (8.5%) false-negative patients and 9 (4.5%) false-positive patients. The Rapirun(®) Stick test has high sensitivity, specificity, and accuracy for the diagnosis of H. pylori infection in the Vietnamese population. The test can be clinically applied in Vietnamese populations.
    World Journal of Gastroenterology 05/2014; 20(17):5087-91. DOI:10.3748/wjg.v20.i17.5087 · 2.43 Impact Factor
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    ABSTRACT: Advances in diagnostic techniques have allowed early stage detection of superficial Barrett's adenocarcinoma (SBA) as well as resection by endoscopic submucosal dissection (ESD). Few reports exist, however, on the safety and efficacy of ESD for SBA. To analyze outcomes of ESD for SBA in relation to clinicopathological features of the lesions. Retrospective study. University hospital. Twenty-three patients (21 men, 2 women; mean age, 63 years) with 26 SBAs. We examined outcomes of ESD in relation to the clinicopathological features of SBAs. The main outcomes assessed were en bloc resection rate, operation time, adverse event rates, additional resection rate, and time between ESD and any recurrence. Twenty lesions (87%) derived from short-segment Barrett's esophagus, and 3 lesions (13%) derived from long-segment Barrett's esophagus. The majority of SBAs (54%) were located in the 0 to 3 o'clock circumferential quadrant. Median tumor size was 15 mm (range 5-60 mm). Macroscopic types were flat elevated (n = 13, 50%), depressed (n = 12, 46%), and protruded (n = 1, 4%). The SBAs appeared red (n = 23, 88%) or normally pale (n = 3, 12%). Under magnifying narrow-band imaging, all SBAs showed an irregular mucosal pattern and an irregular vascular pattern. The endoscopic en bloc resection rate was 100% (26/26), and the pathological en bloc resection rate was 85% (22/26). The median procedure time was 95 minutes (range, 30-210 minutes). Delayed bleeding occurred in 1 case, but there was no perforation. The SBAs were of the differentiated type (n = 25, 96%) or poorly differentiated type (n = 1, 4%). The tumor had invaded the superficial muscularis mucosa (n = 3, 12%), lamina propria mucosa (n = 5, 19%, deep muscularis mucosa (n = 9, 34%), SM1 (n = 3, 12%), and SM2 (n = 6, 23%). Additional surgical resection after ESD was performed in 9 cases, and there were no residual tumors, but 1 lymph node metastasis was found. There were no recurrent tumors; however, 1 metachronous adenocarcinoma was diagnosed 42 months after ESD. Single-center, retrospective study. ESD appears to be a safe and effective treatment strategy for early stage SBA.
    Gastrointestinal endoscopy 02/2014; 80(2). DOI:10.1016/j.gie.2014.01.022 · 4.90 Impact Factor
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    ABSTRACT: Hyperplastic/serrated polyposis syndrome (HPS) is a condition of multiple hyperplastic/serrated colorectal polyps. The risk of colorectal cancer (CRC) is increased in HPS. The clinicopathologic characteristics of HPS in Japanese are unknown. The aim of this study is to clarify the clinicopathologic features of HPS in Japanese patients. We retrieved records of patients with HPS diagnosed between April, 2008 and March, 2011 from the endoscopy database of Hiroshima University Hospital. In addition, we mailed a questionnaire to the hospital's 13 affiliated hospitals in July 2012.We collected data from the database and questionnaires included patient age, sex, number of hyperplastic/serrated polyps and tubular adenomas, size of the largest polyp, polyp location, resection for polyps, co-existence of HPS with CRC, and the WHO criterion met. Of the 73,608 patients who underwent colonoscopy, 10 (0.014%) met the criteria for HPS. Mean age of these patients was 58.3 years, and 6 (60%) were men. No subjects had a first-degree relative with HPS. Four (40%) HPS patients had more than 30 hyperplastic/serrated polyps, and average size of the largest polyp was 19 mm. Three (30%) HPS patients had co-existence of HPS with CRC. In these 3 patients, polyps were observed throughout the colorectum. Although HPS is considered to be a rare condition in the overall study population, the disease may have high risk of CRC. HPS should be diagnosed correctly and followed up carefully.
    Journal of Gastroenterology and Hepatology 06/2013; 28(11). DOI:10.1111/jgh.12307 · 3.63 Impact Factor
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    Article: Response.
    Gastrointestinal endoscopy 06/2013; 77(6):973-974. DOI:10.1016/j.gie.2013.02.004 · 4.90 Impact Factor
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    ABSTRACT: BACKGROUND: The severity of endoscopic gastric atrophy (EGA), high-stage Operative Link on Gastritis Assessment (OLGA) gastritis (i.e., stage III or IV), and extensive intestinal metaplasia (IM) with incomplete subtype have been separately reported as high-risk factors of gastric cancer (GC). The aim of this study was to evaluate the associations between these endoscopic and pathologic characteristics. MATERIALS AND METHODS: A cross-sectional study was conducted on 280 patients with functional dyspepsia at the University Medical Center at Ho Chi Minh City, Vietnam. Biopsies were taken according to the updated Sydney System. EGA was assessed according to the Kimura-Takemoto classification, and gastritis stage was assessed according to the OLGA system. RESULTS: All of patients with high-stage OLGA gastritis (i.e., stage III or IV) clustered in the subgroup of patients with moderate-to-severe EGA: 13/126 (10.3%) in patients with moderate-to-severe EGA versus 0/154 (0%) in patients with none-to-mild EGA (p < .001). Moderate-to-severe EGA was also significantly associated with extensive IM (p < .001, OR = 28.1 (CI 95% 6.4-173.3)) and incomplete IM subtype (p < .001, OR = 36.7 (CI 95% 5.1-742.1). Extensive IM was also associated with incomplete IM subtype (p = .01). CONCLUSIONS: High-stage OLGA gastritis, extensive IM with incomplete subtype clustered in patients with moderate-to-severe EGA. Assessing the severity of EGA could potentially help to identify patients who should be taken systemic biopsy for evaluating GC risk.
    Helicobacter 11/2012; DOI:10.1111/hel.12027 · 2.99 Impact Factor
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    ABSTRACT: BACKGROUND: Whether submucosal fibrosis is related to ulceration and affects the outcome of endoscopic submucosal dissection (ESD) for early gastric cancer (EGC) is unknown. This study aimed to determine ESD outcome in relationship to degree of submucosal fibrosis of gastric epithelial neoplasms and to identify factors predictive of submucosal fibrosis. METHODS: Eight hundred ninety-one patients with 1,027 gastric epithelial neoplasms were treated by ESD from April 2005 to January 2011. Complete en bloc resection and perforation rates in relationship to degree of submucosal fibrosis (F0, no fibrosis; F1; mild fibrosis; F2, severe fibrosis) were determined during ESD, as well as degree of concordance between endoscopically observed ulceration and pathologically determined ulceration and pathological fibrosis stained with Masson's trichrome. RESULTS: The complete en bloc resection rate was significantly low and the perforation rate was high for F2 versus F0/F1 tumors. Ulceration, tumor size ≥30 mm, and depressed histological type were independent risk factors for severe (F2) fibrosis. No fibrosis (F0) was observed in 77 % (732/951) of endoscopically negative ulceration cases, whereas fibrosis was observed in 100 % (76/76) of endoscopically positive cases. Masson trichrome staining was weak in 97 % (710/732) of F0, moderate in 85 % (181/214) of F1, and strong in 100 % (81/81) of F2 cases. CONCLUSIONS: Histopathological type of submucosal fibrosis predicts outcome of ESD for EGC. Endoscopic indications of F2 submucosal fibrosis are ulceration, tumor ≥30 mm, and macroscopic depression.
    Gastric Cancer 10/2012; 16(3). DOI:10.1007/s10120-012-0203-0 · 4.83 Impact Factor
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    ABSTRACT: BACKGROUND: Endoscopic detection of superficial squamous epithelial lesions of the pharynx has increased. OBJECTIVE: To clarify the association between macroscopic and histologic characteristics of intraepithelial pharyngeal neoplasias, and to evaluate the effectiveness of endoscopic submucosal dissection (ESD) for their treatment. DESIGN: Retrospective analysis of the features of high-grade dysplasia or carcinoma in situ (HGD/CIS) versus low-grade dysplasia (LGD) and of ESD-based outcomes. SETTING: Endoscopy department at a university hospital. PATIENTS: Fifty-one patients with 66 lesions treated by ESD from November 2007 to March 2011. RESULTS: Primary hypopharyngeal lesions were significantly more frequent in HGD/CIS than in LGD (54.1% vs 20.7%, P = .011), and oropharyngeal lesions were significantly less frequent in HGD/CIS (45.9% vs 79.3%, P = .011). HGD/CIS lesions were significantly larger than LGD lesions (median 8 mm vs 4 mm, P < .01). Morphologically, type 0-IIa was significantly more frequent in HGD/CIS lesions than in LGD lesions (37.8% vs 3.4%, P < .001), and type 0-IIb was significantly less frequent in HGD/CIS lesions (59.5% vs 96.6%, P < .001). The type IV intraepithelial papillary capillary loop pattern was significantly less frequent in HGD/CIS lesions than in LGD lesions (27.0% vs 55.2%, P = .025), and type V-2 was significantly more frequent in HGD/CIS lesions (18.9% vs 0%, P = .015). The en bloc resection rate was 97%. No serious complications occurred. There were no recurrent or metachronous tumors in the 41 patients followed for more than 1 year (median follow-up 27 months). LIMITATIONS: Retrospective design and single-center study. CONCLUSIONS: HGD/CIS and LGD differ in various clinical features. ESD appears to be an effective treatment for pharyngeal intraepithelial neoplasias.
    Gastrointestinal endoscopy 09/2012; 76(6). DOI:10.1016/j.gie.2012.07.032 · 4.90 Impact Factor
  • Gastrointestinal Endoscopy 04/2012; 75(4):AB499. DOI:10.1016/j.gie.2012.03.1364 · 4.90 Impact Factor
  • Gastrointestinal Endoscopy 04/2012; 75(4):AB348. DOI:10.1016/j.gie.2012.03.909 · 4.90 Impact Factor
  • The American Journal of Gastroenterology 01/2012; 107(1):143-4. DOI:10.1038/ajg.2011.321 · 9.21 Impact Factor
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    American journal of infection control 12/2011; 40(1):80. DOI:10.1016/j.ajic.2011.09.004 · 2.33 Impact Factor
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    ABSTRACT: The 2010 Japanese Gastric Cancer Association guidelines for the treatment of submucosal invasive gastric cancer (SM-GC) specify size 30 mm or less, differentiated-dominant histology, lack of vessel involvement, and submucosal invasion of less than 500 μm (SM1) as expanded criteria for curative endoscopic resection. Our purpose in this study was to confirm the validity of the expanded indications for curative endoscopic submucosal dissection (ESD) of SM-GC. The study subjects were 173 patients with SM-GC resected by ESD at Hiroshima University Hospital between April 2002 and September 2010, including 99 patients for whom 3-plus years' follow-up information was available. Post-ESD outcomes were compared between cases of SM1-GC that met the expanded ESD criteria, those that did not, and SM2-GC cases. Complete resection was achieved for 93.2% of the SM1-GCs that met the expanded criteria. There was neither metastasis to lymph nodes or other organs nor local recurrence among the SM1-GCs. Disease-specific survival did not differ significantly between patients that were simply followed up after ESD and those that were treated by additional surgical resection. Our outcome data support the clinical validity of ESD without additional surgical resection for SM1-GCs that meet the expanded criteria.
    Gastric Cancer 07/2011; 15(1):97-105. DOI:10.1007/s10120-011-0076-7 · 4.83 Impact Factor
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    ABSTRACT: Serrated adenomas (SAs), recently subdivided into traditional SAs (TSAs) and sessile SAs (SSAs), are recognized as a distinct form of neoplasia of the colorectum. One of the characteristics of SAs is hypermaturation of the gland epithelium due to the low extent of cell loss by apoptosis. Mutations of mitochondrial DNA (mtDNA) are closely associated with abnormality in apoptosis. We therefore examined mtDNA mutations in colorectal lesions including hyperplastic polyps (HPs), SSAs, TSAs, and carcinomas. Examined were 25 HPs, 32 SSAs, 19 TSAs, and 138 carcinomas. The D310 region of the mtDNAs was examined by microsatellite assay. mtDNA mutations were detected in none of 25 (0%) HPs, one of 32 (3%) SSAs, six of 19 (32%) TSAs, and eleven of 133 (8%) carcinomas (five of the 138 carcinomas were not informative). The frequency of mtDNA mutations in the TSAs was significantly higher than that in the HPs, SSAs, and carcinomas (P = 0.004, P = 0.008, and P = 0.009, respectively). The frequency of mtDNA mutations in carcinomas was not significantly higher than that in HPs and SSAs (P = 0.14 and P = 0.28, respectively). Our data suggest that mtDNA mutations may play an important role in the development of TSAs and could be used as a genetic marker to aid in the diagnosis of colorectal lesions.
    Journal of Gastroenterology and Hepatology 06/2011; 26(10):1565-9. DOI:10.1111/j.1440-1746.2011.06797.x · 3.63 Impact Factor
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    ABSTRACT: To examine the frequency and prevention of musculoskeletal pain in Japanese gastrointestinal endoscopists and non-endoscopist physicians. Questionnaires were sent to 275 endoscopists and 173 non-endoscopists working in Hiroshima University Hospital and its affiliated hospitals. The completed questionnaires were returned by 190 (69%) endoscopists and 120 (69%) non-endoscopists. The frequency of pain in the hand and wrist, and especially the left thumb, was significantly higher in endoscopists than in non-endoscopists (17% vs 6%, P = 0.004). Using multivariate analysis, the only significant factor associated with this pain was the age of the endoscopist (odds ratio 2.77, 95% confidence interval, 1.23-6.71, P = 0.018). Interestingly, endoscopists had made significantly fewer modifications to their endoscopic practices than non-endoscopists (12% vs 33%, P < 0.0001) to prevent pain. Pain in the hand and wrist may be endoscopy-related. However, endoscopists made little modifications in practice to prevent such pain. More attention to prevention appears necessary.
    World Journal of Gastroenterology 03/2011; 17(11):1488-93. DOI:10.3748/wjg.v17.i11.1488 · 2.43 Impact Factor
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    ABSTRACT: We describe successful removal a sewing needle penetrating the wall of the third portion of the duodenum by means of double-balloon endoscopy (DBE). The patient was a 47-year-old woman who accidentally swallowed a sewing needle and was admitted to our hospital. Abdominal radiography and abdominal computed tomography revealed a metallic object in the third portion of the duodenum. DBE performed by the antegrade approach, revealed that the sewing needle had penetrated the duodenal wall. The sewing needle was retrieved with biopsy forceps and pulled out together with the endoscope through the flexible overtube that remained positioned in the duodenum. There was no injury to the patient’s esophagus or gastrointestinal wall. Our experience in this case suggests that sharp foreign bodies in the gastrointestinal tract can be safely removed by means of DBE.
    Clinical Journal of Gastroenterology 02/2011; 5(1). DOI:10.1007/s12328-011-0274-1

Publication Stats

1k Citations
397.40 Total Impact Points


  • 1999–2015
    • Hiroshima University
      • • Health Service Center
      • • Department of Gastroenterology and Metabolism
      Hirosima, Hiroshima, Japan
  • 2003–2004
    • Kawasaki Medical University
      • Department of General Internal Medicine 2
      Kurasiki, Okayama, Japan