Shiro Oka


Affiliation: Hiroshima University
Country: Japan


  1. Yamashita K, Oka S, Tanaka S, Nagata S, Kuwai T, Furudoi A, et al. Long-term prognosis after treatment for T1 carcinoma of laterally spreading tumors: a multicenter retrospective study. Int J Colorectal Dis. 2019;34:481-490 pubmed publisher
    ..Our data supported adequacy of the JSCCR guidelines for the treatment of CRC criteria for endoscopically curable patients after T1 LSTs treatment. Patients with T1 LST-G-M should be followed up more carefully. ..
  2. Tanaka H, Oka S, Tanaka S, Matsumoto K, Boda K, Yamashita K, et al. Dual Red Imaging Maintains Clear Visibility During Colorectal Endoscopic Submucosal Dissection. Dig Dis Sci. 2019;64:224-231 pubmed publisher
    ..5%) are the predictive factors of severe submucosal fatty tissue. DRI is useful in maintaining clear visibility during colorectal ESD, especially with submucosal fatty tissue. ..
  3. Ninomiya Y, Oka S, Tanaka S, Nishiyama S, Tamaru Y, Asayama N, et al. Risk of bleeding after endoscopic submucosal dissection for colorectal tumors in patients with continued use of low-dose aspirin. J Gastroenterol. 2015;50:1041-6 pubmed publisher
    ..No significant difference was seen between the LDA-continued group and the LDA-interrupted group. ..
  4. Shishido T, Oka S, Tanaka S, Aoyama T, Watari I, Imagawa H, et al. Removal of a sewing needle penetrating the wall of the third portion of the duodenum by double-balloon endoscopy. Clin J Gastroenterol. 2012;5:79-81 pubmed publisher
    ..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. ..
  5. Nishiyama S, Oka S, Tanaka S, Sagami S, Nagai K, Ueno Y, et al. Clinical usefulness of endocytoscopy in the remission stage of ulcerative colitis: a pilot study. J Gastroenterol. 2015;50:1087-93 pubmed publisher
    ..The ECSS may be a predictive indicator for UC relapse since there was a correlation between the ECSS and the degree of inflammation as determined by histopathology. ..
  6. Yoshifuku Y, Oka S, Tanaka S, Sanomura Y, Miwata T, Numata N, et al. Long-term prognosis after endoscopic submucosal dissection for early gastric cancer in super-elderly patients. Surg Endosc. 2016;30:4321-9 pubmed publisher
    ..However, patients with comorbidities are at a high risk of poor prognosis. ..
  7. Asayama N, Oka S, Tanaka S, Hirano D, Sumimoto K, Ninomiya Y, et al. Pedunculated-type T1 colorectal carcinoma with lung carcinoma metastasis at the deepest invasive portion. Clin J Gastroenterol. 2016;9:208-14 pubmed publisher
    ..From these morphological and immunohistochemical findings, the final diagnosis was moderately differentiated lung carcinoma, pTX N3 M1b (LN, colon) Stage IV. ..
  8. Asayama N, Oka S, Tanaka S, Nagata S, Furudoi A, Kuwai T, et al. Long-term outcomes after treatment for pedunculated-type T1 colorectal carcinoma: a multicenter retrospective cohort study. J Gastroenterol. 2016;51:702-10 pubmed publisher
    ..Our data support the validity of the JSCCR curative criteria for pedunculated-type T1 CRCs. Endoscopic resection cannot be considered curative for pedunculated-type T1 CRC with head invasion alone. ..
  9. Asayama N, Oka S, Tanaka S, Ninomiya Y, Tamaru Y, Shigita K, et al. Long-term outcomes after treatment for T1 colorectal carcinoma. Int J Colorectal Dis. 2016;31:571-8 pubmed publisher
    ..Long-term outcomes support the curative criteria according to the JSCCR guidelines. ER for T1 CRC did not worsen clinical outcomes in cases that required additional surgical resection. ..

More Information


  1. Miwata T, Oka S, Tanaka S, Kagemoto K, Sanomura Y, Urabe Y, et al. Risk factors for esophageal stenosis after entire circumferential endoscopic submucosal dissection for superficial esophageal squamous cell carcinoma. Surg Endosc. 2016;30:4049-56 pubmed publisher
    ..Our data suggest that refractory post-ESD stenosis occurs after entire circumferential esophageal ESD with muscle layer damage and ≥5 cm of longitudinal mucosal defect length. ..
  2. Tamaru Y, Oka S, Tanaka S, Hiraga Y, Kunihiro M, Nagata S, et al. Endoscopic submucosal dissection for anorectal tumor with hemorrhoids close to the dentate line: a multicenter study of Hiroshima GI Endoscopy Study Group. Surg Endosc. 2016;30:4425-31 pubmed publisher
    ..No recurrence occurred during the follow-up period of 38 months. ESD is safe and effective for anorectal tumors close to the dentate line in patients with hemorrhoids. ..
  3. Igawa A, Oka S, Tanaka S, Kunihara S, Nakano M, Aoyama T, et al. Major predictors and management of small-bowel angioectasia. BMC Gastroenterol. 2015;15:108 pubmed publisher
    ..Type 1a angioectasias with oozing are indicated for PDI and type 1b angioectasias are indicated for PDI with APC or clipping. ..
  4. Tamaru Y, Oka S, Tanaka S, Nagata S, Hiraga Y, Kuwai T, et al. Long-term outcomes after treatment for T1 colorectal carcinoma: a multicenter retrospective cohort study of Hiroshima GI Endoscopy Research Group. J Gastroenterol. 2017;52:1169-1179 pubmed publisher
    ..Our findings supported the JSCCR criteria for endoscopically curable T1 CRC. ER for T1 CRC did not worsen the clinical outcomes of patients who required additional surgical resection. ..
  5. Miwata T, Hiyama T, Quach D, Le H, Hua H, Oka S, et al. Differences in K-ras and mitochondrial DNA mutations and microsatellite instability between colorectal cancers of Vietnamese and Japanese patients. BMC Gastroenterol. 2014;14:203 pubmed publisher
    ..These results indicate that the developmental pathways of CRCs in the Vietnamese may differ from those of CRCs in the Japanese. ..
  6. Numata N, Oka S, Tanaka S, Yoshifuku Y, Miwata T, Sanomura Y, et al. Useful condition of chromoendoscopy with indigo carmine and acetic acid for identifying a demarcation line prior to endoscopic submucosal dissection for early gastric cancer. BMC Gastroenterol. 2016;16:72 pubmed publisher
    ..5 % (5/67) in useless cases. Before ESD, chromoendoscopy with indigo carmine and acetic acid can be used for creating precise markings in protruded or flat elevated-type EGC or at the atrophic border on the oral side of EGCs. ..
  7. Hirano D, Oka S, Tanaka S, Sumimoto K, Ninomiya Y, Tamaru Y, et al. Clinicopathologic and endoscopic features of early-stage colorectal serrated adenocarcinoma. BMC Gastroenterol. 2017;17:158 pubmed publisher
    ..Epithelial serration in the cancerous area and a non-TSA background indicated aggressive behavior in early-stage SACs. ..
  8. Yoshifuku Y, Sanomura Y, Oka S, Kurihara M, Mizumoto T, Miwata T, et al. Evaluation of the visibility of early gastric cancer using linked color imaging and blue laser imaging. BMC Gastroenterol. 2017;17:150 pubmed publisher
    ..The improvement in visibility was significantly higher with LCI than that with BLI. ..