Toru Hiyama

Prof. Toru Hiyama

orcid

Research Focus & Metrics

Academic Career Length

29Years (1998-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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14 August 2007 in International Journal of Cancer
Verified
Journal Article
Open access
PDF file
THToru Hiyama
Toru Hiyama
MYMasaharu Yoshihara
Masaharu Yoshihara
STShinji Tanaka
Shinji Tanaka
KCKazuaki Chayama
Kazuaki Chayama
The aim of this paper is to review and evaluate, in a comprehensive manner, the published data regarding the contribution of genetic polymorphisms to risk of esophageal cancer, including squamous cell carcinoma (SCC) and adenocarcinoma, in humans. All relevant studies available in MEDLINE and published before February 2007 were identified. Studies carried out in humans and that compared esophageal cancer patients with at least 1 standard control group were considered for analysis. One‐hundred studies and 3 meta‐analyses were identified. Eighty (80%) studies were conducted in Asian countries, particularly China including Taiwan (60 (60%) studies). The most intensively examined genes were those encoding carcinogen metabolic enzymes. The most widely studied gene was GSTM1 (15 studies), followed by ALDH2 (11 studies). ALDH2, MTHFR C677T, CYP1A1 Ile/Val, CYP1A1MspI, CYP2E1, GSTP1, GSTM1 and GSTT1 were examined by meta‐analyses and significant relations were found between ALDH2*1*2 and the CYP1A1 Val allele and increased risk of esophageal cancer. In addition, increased risk of esophageal SCC was consistently associated with the ADH2*1*2 and the p53 codon 72 Pro/Pro genotypes. Cohort studies that simultaneously consider multiple genetic and environmental factors possibly involved in esophageal carcinogenesis are needed to ascertain not only the relative contribution of these factors to tumor development but also the contributions of their putative interactions.

8 February 2007 in Journal of Gastroenterology and Hepatology
Verified
Journal Article
Closed access
PDF file
THToru Hiyama
Toru Hiyama
MYMasaharu Yoshihara
Masaharu Yoshihara
Keitaro MatsuoKeitaro Matsuo
Keitaro Matsuo
HKHiroaki Kusunoki
Hiroaki Kusunoki
TKTomoari Kamada
Tomoari Kamada
KHKen Haruma
Ken Haruma

1 January 2006 in World Journal of Gastroenterology
Verified
Journal Article
Open access
THToru Hiyama
Toru Hiyama
MYMasaharu Yoshihara
Masaharu Yoshihara
STShinji Tanaka
Shinji Tanaka
YUYuji Urabe
Yuji Urabe
YIYoshihiko Ikegami
Yoshihiko Ikegami
KCKazuaki Chayama
Kazuaki Chayama
AIM: To clarify the prevalence of defensive medicine and the specific defensive medicine practices among gastroenterologists in Japan. METHODS: A survey of gastroenterologists in Hiroshima, Japan, was conducted by mail in March 2006. The number of gastroenterologists reporting defensive medicine behaviors or changes in their scope of practice and the reported defensive medicine practices, i.e., assurance and avoidance behaviors, were examined. RESULTS: A total of 131 (77%) out of 171 gastroenterologists completed the survey. Three (2%) respondents were sued, and most respondents (96%) had liability insurance. Nearly all respondents (98%) reported practicing defensive medicine. Avoidance behaviors, such as avoiding certain procedures or interventions and avoiding caring for high-risk patients, were very common (96%). Seventy-five percent of respondents reported often avoiding certain procedures or interventions. However, seasoned gastroenterologists (those in practice for more than 20 years) adopted avoidance behaviors significantly less often than those in practice for less than 10 years. Assurance behaviors, i.e., supplying additional services of marginal or no medical value, were also widespread (91%). Sixty-eight percent of respondents reported that they sometimes or often referred patients to other specialists unnecessarily. CONCLUSION: Defensive medicine may be highly prevalent among gastroenterologists throughout Japan, with potentially serious implications regarding costs, access, and both technical and interpersonal quality of care.

8 December 2017 in BMC Gastroenterology
Verified
Journal Article
Open access
PDF file
YYYoshikazu Yoshifuku
Yoshikazu Yoshifuku
YSYoji Sanomura
Yoji Sanomura
SOShiro Oka
Shiro Oka
MKMio Kurihara
Mio Kurihara
TMTakeshi Mizumoto
Takeshi Mizumoto
KCKazuaki Chayama
Kazuaki Chayama
Blue laser imaging (BLI) and linked color imaging (LCI) are the color enhancement features of the LASEREO endoscopic system, which provide a narrow band light observation function and expansion and reduction of the color information, respectively. We examined 82 patients with early gastric cancer (EGC) diagnosed between April 2014 and August 2015. Five expert and 5 non-expert endoscopists retrospectively compared images obtained on non-magnifying BLI bright mode (BLI-BRT) and LCI with those obtained via conventional white light imaging (WLI). Interobserver agreement was also assessed. In experts’ evaluation of the images, an improvement in visibility was observed in 73% (60/82) and 20% (16/82) of cases under LCI and BLI-BRT, respectively. In non-experts’ evaluation of the images, an improvement in visibility was observed in 76.8% (63/82) and 24.3% (20/82) of cases under LCI and BLI-BRT, respectively. There were no significant differences between experts and non-experts in the evaluation of the images. The improvement in visibility was significantly higher with LCI than with BLI-BRT in experts and non-experts (p < 0.01). With regard to tumor color on WLI, the improvement in the visibility of reddish and whitish tumors was significantly higher than that of isochromatic tumors when LCI was used. The improvement in visibility with LCI was observed in 71% (12/17) and 74% (48/65) of patients with and without Helicobacter pylori (Hp) eradication, respectively; no significant difference in improvement was observed between these groups. The interobserver agreement was good to satisfactory at ≥ 0.62. In conclusion, our study showed that LCI improved the visibility of EGC, regardless of the level of endoscopists’ experience or Hp eradication in patients, particularly for EGCs with a reddish or whitish color. The improvement in visibility was significantly higher with LCI than that with BLI.

1 January 2011 in World Journal of Gastroenterology
Verified
Journal Article
Open access
TKTakayasu Kuwabara
Takayasu Kuwabara
YUYuji Urabe
Yuji Urabe
THToru Hiyama
Toru Hiyama
STShinji Tanaka
Shinji Tanaka
TSTakako Shimomura
Takako Shimomura
KCKazuaki Chayama
Kazuaki Chayama
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.

11 September 2010 in Journal of Gastroenterology and Hepatology
Verified
Journal Article
Closed access
PDF file
YUYuji Urabe
Yuji Urabe
THToru Hiyama
Toru Hiyama
STShinji Tanaka
Shinji Tanaka
MYMasaharu Yoshihara
Masaharu Yoshihara
KAKoji Arihiro
Koji Arihiro
KCKazuaki Chayama
Kazuaki Chayama