Tai Omori

Keio University, Edo, Tōkyō, Japan

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Publications (91)255.22 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Esophagectomy is one of the most invasive surgical treatments for digestive tract cancer, and the blood levels of inflammatory cytokines such as interleukin-1, interleukin-6, and interleukin-8 are increased for several hours after surgery or in patients experiencing postoperative complications. CXCR2, an interleukin-8 receptor, is reportedly expressed in several carcinomas, and interleukin-8 signaling promotes cancer cell proliferation. The impact of postoperative complications following esophagectomy on long-term survival is controversial. In this study, we demonstrate the significance of CXCR2 expression and validate the effects of CXCR2 expression and postoperative complications on long-term prognosis of esophageal squamous cell carcinoma using resected specimens. Eighty-two specimens were sectioned from archived, paraffin-embedded tumor tissues obtained from patients with esophageal squamous cell carcinoma who underwent esophagectomy and extended lymphadenectomy for complete resection of cancer in our institute between 1997 and 2002. Immunohistochemistry was performed using a polyclonal antibody to CXCR2, and the correlation of stainability with clinicopathological factors and long-term survival was examined. CXCR2 was expressed in 33 of 82 (40.2 %) specimens. In the CXCR2-positive group, the recurrence-free survival and overall survival rates of patients who developed postoperative complications were both significantly lower than those for patients who did not develop any complications. In contrast, in the CXCR2-negative group, there was no significant difference in long-term prognosis between patients with and without complications. CXCR2 positivity combined with postoperative complications was an independent risk factor for subsequent tumor recurrence, showing the highest hazard ratio. Our results suggest that the patients with CXCR2-positive esophageal cancer who develop postoperative complications have a poor prognosis and should be carefully followed. Trial registration This study was approved by Keio University School of Medicine Ethics Committee with a trial registration number of 2011-241.
    World Journal of Surgical Oncology 08/2015; 13(1):232. DOI:10.1186/s12957-015-0658-7 · 1.41 Impact Factor
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    ABSTRACT: The aim of this study was to assess the impact of postoperative complications after esophagectomy on long-term outcome.The treatment of esophageal cancer has recently been improved; however, esophagectomy with thoracotomy and laparotomy carries considerable postoperative morbidity and mortality. The real impact of postoperative complications on overall survival is still under evaluation.A retrospective analysis was performed on patients with esophageal cancer who underwent esophagectomy with thoracotomy and laparotomy, with R0 or R1 resection between January 1997 and December 2012. Of 402 patients, we analyzed the following parameters 284 patients who could be followed up for over 5 years: stage of disease, neoadjuvant therapies, surgical approaches, surgical complications, postoperative medical complications, and overall and relapse-free survivals using medical records.Of the 284 patients, 64 (22.5%) had pneumonia, 55 (19.4%) had anastomotic leakage, and 45 (15.8%) had recurrent laryngeal nerve paralysis (RLNP). Pneumonia had a significant negative impact on overall survival (P = 0.035); however, anastomotic leakage and RLNP did not affect overall survival. Multivariate analysis revealed that the presence of pneumonia was predictive of poorer overall survival; the multivariate hazard ratio was 1.456 (95% confidence interval 1.020-2.079, P = 0.039).Pneumonia has a negative impact on overall survival after esophagectomy. Strategies to prevent pneumonia after esophagectomy should improve outcomes in this operation.
    Medicine 08/2015; 94(33):e1369. DOI:10.1097/MD.0000000000001369 · 5.72 Impact Factor
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    ABSTRACT: Drug resistance to chemotherapy is a major issue in esophageal cancer management. Drug resistance may be mediated by genetic changes in the tumor; therefore, the identification of gene mutations may lead to better therapeutic outcomes. We used a novel method involving transposons to screen and identify drug-resistant genes. Transposons are DNA sequences that move from one location on the gene to another. A modified piggyBac transposon was designed as an insertion mutagen, and a cytomegalovirus (CMV) promoter sequence was added to induce strong transcription. When the transposon is inserted to the upstream of a certain gene, the gene will be overexpressed while when intserted down or intragenically, it will be downregulated. After establishing a transposon-tagged cell library, we treated cell lines derived from esophageal squamous cell carcinomas (ESCC) [Tohoku esophagus (TE)] with cisplatin (CDDP). We performed splinkerette PCR and TOPO cloning on the resistant colonies. Bacterial colonies were sequenced, and next-generation sequencing was used to identify the overexpressed/downregulated sequences as candidate genes for CDDP resistance. We established 4 cell lines of transposon-tagged cells, TE4, 5, 9 and 15. We treated the two relatively viable cell lines, TE4 and TE15, with CDDP. We identified 37 candidate genes from 8 resistant colonies. Eight genes were overexpressed whilst 29 were downregulated. Among these genes was Janus kinase 2 (JAK2) that is implicated in the progression of myeloproliferative neoplasms. We identified 37 candidate genes responsible for CDDP resistance in the two cell lines derived from ESCC cells. The method is inexpensive, relatively simple, and capable of introducing activating and de-activating mutations in the genome, allowing for drug-resistant genes to be identified.
    International Journal of Oncology 07/2015; 47(3). DOI:10.3892/ijo.2015.3085 · 3.03 Impact Factor
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    ABSTRACT: During the treatment of esophageal cancer with curative intent, patients sometimes experience deep vein thrombosis, pulmonary embolism or a central venous catheter-associated thrombus. In this study, we retrospectively reviewed our new-onset esophageal cancer patients and determined the incidence of venous thromboembolism (VTE), the location of the thrombus and the risk factors for VTE. One hundred and fifty-three patients undergoing treatment with curative intent were reviewed as candidates. The existence of VTE was assessed from the neck to the pelvis with computed tomography at the initial visit, after neo-adjuvant chemotherapy and postoperatively. Twenty-one VTE events (13.7 %) were observed, 16 of which (76.2 %) were suggested to be associated with central venous catheterization. When both the pre-therapeutic plasma fibrinogen and C-reactive protein levels were high (≥350 mg/dL and ≥0.2 µg/mL, respectively), the risk of preoperative VTE and overall VTE were significantly higher than normal (p = 0.040, and p = 0.030, respectively). Adenocarcinoma histology and neck lymph node dissection were the independent risk factors that significantly increased the overall risk of VTE (p = 0.015, and p = 0.017, respectively). This study revealed that the pre-therapeutic plasma fibrinogen level, C-reactive protein level, adenocarcinoma histology and neck lymph node dissection are the risk factors for venous thromboembolism in patients with esophageal cancer undergoing treatment with curative intent.
    Surgery Today 06/2015; DOI:10.1007/s00595-015-1196-1 · 1.53 Impact Factor
  • Gastrointestinal Endoscopy 05/2015; 81(5):AB520. DOI:10.1016/j.gie.2015.03.1775 · 5.37 Impact Factor
  • Gastrointestinal Endoscopy 05/2015; 81(5):AB519. DOI:10.1016/j.gie.2015.03.1772 · 5.37 Impact Factor
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    ABSTRACT: Purpose/Aim: We performed a randomized, prospective animal study to investigate whether inhibiting the renin-angiotensin system with a (pro)renin receptor blocker (PRRB) prevents acute lung injury (ALI) in a rodent model. We used Thirty-six male Sprague-Dawley rats. We administered lipopolysaccharide (LPS; 2 mg/kg) intratracheally with or without PRRB pretreatment (1 mg/kg/d). We performed bronchoalveolar lavage (BAL) and lung removal at 4 h after LPS administration and measured levels of inflammatory cytokines, high mobility group box 1 (HMGB-1) protein, and total protein in bronchoalveolar lavage fluid (BALF). Myeloperoxidase (MPO) activity was detected in lung tissue homogenates using a sensitive ELISA. We performed hematoxylin and eosin staining and immunohistochemical staining for nonproteolytically activated prorenin in the left lung. The PRRB decreased leukocyte counts and total protein, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-2, IL-6, and IL-10 levels in the BALF and MPO activity in lung tissue. The PRRB reduced interstitial edema, hemorrhage, and the neutrophil count in the lung tissues. Consistent with the reduction in lung tissue damage, immunohistochemical staining showed that the PRRB decreased the amount of nonproteolytically activated prorenin. The PRRB blocked LPS-induced inflammatory response in the lung and protected against ALI. Therefore, it is a potential therapeutic agent for preventing ALI.
    Experimental Lung Research 04/2015; 41(4):1-9. DOI:10.3109/01902148.2014.993444 · 1.41 Impact Factor
  • Gastroenterology 04/2015; 148(4):S-351-S-352. DOI:10.1016/S0016-5085(15)31181-1 · 16.72 Impact Factor
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    ABSTRACT: Background Recent improvements in the survival of patients after esophagectomy have led to an increasing occurrence of gastric cancer in the reconstructed gastric tube (GTC). The aim of this study was to assess generational changes in the clinicopathological characteristics and treatment of GTCs in a single center. Methods Thirteen GTC lesions in ten patients were diagnosed and treated at Keio University Hospital between 2006 and 2014. In our previous study, we reported eight cases of GTC [1]. We compared clinicopathological characteristics and treatment of GTC, as well as overall survival achieved in this study with those in our previous study [1]. Results In this study, median patient age at the time of GTC detection was 74 years (range 62-81 years) and the median interval between esophagectomy and GTC detection was 95 months (range 21-159 months). Nine (69 %) of 13 lesions satisfied the criteria for endoscopic resection. On comparing this study with our previous study, there were no significant differences in patient age at the time of GTC detection, the interval between esophagectomy and GTC detection, or pathological stage [1]. Compared with our previous study, the use of less invasive treatments, such as endoscopic submucosal dissection and partial gastric tube resection with sentinel lymph node dissection, generationally increased and a significant difference was observed in the type of GTC treatment [1]. However, there was no significant difference in overall survival between the studies. Conclusion Long-term periodic endoscopy permits less invasive treatments and combinations of various treatments for effective GTC therapy.
    Esophagus 03/2015; DOI:10.1007/s10388-015-0491-7 · 0.74 Impact Factor
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    ABSTRACT: Background Serum bilirubin levels frequently increase after esophagectomy for esophageal cancer. Several studies have reported hyperbilirubinemia in patients with postoperative complications. We aimed to perform a detailed large-scale analysis to clarify this association. Methods We compared postoperative serum bilirubin levels of 200 patients with esophageal cancer who underwent esophagectomy, with and without postoperative complications, from January 2008 to July 2013 at Keio University Hospital, Tokyo, Japan. We also analyzed other risk factors for postoperative hyperbilirubinemia by univariate and multivariate analyses in an attempt to determine the mechanism of postoperative hyperbilirubinemia. Results Hyperbilirubinemia (total bilirubin >2.0 mg/dL) occurred in 71 patients (35.5 %). The mean total bilirubin peak level was 1.5 mg/dL in patients without complications, 2.0 mg/dL in those with at least one complication, 2.1 mg/dL in those with pneumonia, and 2.3 mg/dL in those with anastomotic leakage. Bilirubin levels were significantly higher in each complication group than in the non-complication group (p
    World Journal of Surgery 01/2015; 39(5). DOI:10.1007/s00268-014-2936-x · 2.64 Impact Factor
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    ABSTRACT: Background Basaloid squamous cell carcinoma (BSCC) is a relatively rare, malignant disease of the esophagus. The prognosis of patients with BSCC is thought to be poorer than that of typical squamous cell carcinoma (SCC), but the treatment strategy for BSCC is generally the same as that for typical SCC. This study examined the diagnosis, the clinical and pathological characteristics, and the results of therapy in patients with BSCC. Methods The medical records for 13 patients with pathologically confirmed esophageal BSCC were extracted. The pretreatment endoscopic diagnosis and the pathological diagnosis after resection were reviewed for each patient, and the histological features and patient outcome were examined. We especially focus on histological difference and endoscopic findings of the 13 patients with BSCC. Results Macroscopically, BSCC was mainly visualized as an elevated lesion with normal epithelium on the surface layer which indicated the tumor growth into submucosa. Further pathological examination allowed the 13 BSCC patients to be grouped into 2 groups according to differences in the microscopic appearances of the BSCC cancer cells: a typical BSCC pattern and a pattern similar to that of poorly differentiated SCC. Six of the patients who received an esophagectomy as the primary treatment died, and only 1 patient survived. Two patients who received chemoradiotherapy before an esophagectomy did not develop recurrences. Almost all the patients who died as a result of the recurrence of esophageal cancer had a lymph node recurrence. Prognoses of BSCCs with a pattern similar to that of poorly differentiated SCC without preoperative chemotherapy were poorer than BSCCs with a typical BSCC pattern, while BSCC with a pattern similar to poorly differentiated SCC with preoperative chemotherapy showed good prognoses than BSCC without preoperative chemotherapy. Conclusions BSCC esophageal cancer mainly appears as an elevated lesion with submucosal growth, which can be diagnosed preoperatively by understanding of macroscopic characteristics of esophageal BSCC. The outcome of the BSCC patients in the present study was relatively poor, while pretreatment diagnosis of BSCC influences the strategy of treatment and pathological diagnosis including histological difference of BSCC may lead to appropriate treatment and better prognosis of esophageal BSCC.
    Esophagus 01/2015; DOI:10.1007/s10388-015-0490-8 · 0.74 Impact Factor
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    ABSTRACT: We experienced a patient with superficial hypopharyngeal cancer in whom a steroid injection effectively prevented postoperative adhesions and stenosis. The patient was a 59-year-old man who had undergone an esophagectomy for esophageal cancer and was diagnosed with superficial hypopharyngeal cancer 1 year later. He underwent endoscopic laryngo-pharyngeal surgery after a detailed examination. No postoperative adhesions or stenosis occurred after the steroid injection. Steroids inhibit postoperative adhesions and stenosis through their anti-inflammatory and fibrosis-inhibiting effects. A steroid injection is easier than other procedures, such as endoscopic balloon dilation or incision, and causes little pain or risk for patients. A steroid injection is effective and useful for preventing postoperative adhesions and stenosis in a patient with superficial hypopharyngeal cancer.
    01/2015; 86(1):114-115. DOI:10.11641/pde.86.1_114
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    ABSTRACT: We describe a patient with solitary lymph node (LN) metastasis after three endoscopic mucosal resections (EMRs) in which a gastrointestinal stromal tumor was difficult to differentiate from the carcinoid and lymphoma tumors. A 77-year-old man underwent three EMRs at 62, 72, and 75 years of age, and all resections were determined to be curative. However, 2 years after the last EMR, screening abdominal ultrasonography detected a 20-mm solitary tumor at the lesser curvature of the upper stomach. Laparoscopic tumor resection confirmed the pathological diagnosis. Intraoperative pathological diagnosis showed that the adenocarcinoma was compatible with recurrence of gastric cancer; thus, total gastrectomy with D1 lymphadenectomy was performed. Metastasis was not recognized by pathological examination but was detected by preoperative radiological examinations of the LN. We report a rare recurrence case after several EMRs of intramucosal gastric cancers.
    World Journal of Surgical Oncology 11/2014; 12(1):339. DOI:10.1186/1477-7819-12-339 · 1.41 Impact Factor
  • Cancer Research 10/2014; 74(19 Supplement):50-50. DOI:10.1158/1538-7445.AM2014-50 · 9.33 Impact Factor
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    ABSTRACT: Background Brain metastasis from esophageal carcinoma is uncommon. The aims of this study were to assess the frequency of brain metastasis from esophageal carcinoma, describe treatment modalities and their outcomes, and determine predictors of survival. Methods Between 2004 and 2012, 680 patients with esophageal carcinoma were registered at Keio University Hospital, Tokyo, Japan. Of these patients, 16 (2.3 %) were diagnosed with brain metastasis. We reviewed their medical records and performed statistical analyses. Results The median survival after diagnosis of brain metastasis was 5.0 months (95 % CI 1.2–8.7 months). The only statistically significant baseline characteristic that predicted worse survival from brain metastasis was the onset form of brain metastasis (p = 0.01). At the onset of brain metastasis, the median survival from brain metastasis was 13.0 months (95 % CI 0.0–31.0 months) in patients without extracranial metastasis and 2.0 months (95 % CI 0.0–4.3 months) in patients with extracranial metastasis (p = 0.01). Conclusions Approximately 2 % patients with esophageal carcinoma were diagnosed with brain metastasis. The prognosis of brain metastasis is extremely poor, but long-term survival may be expected with intensive treatment for brain metastasis when the first metastatic site is the brain.
    Esophagus 09/2014; 11(4):217-222. DOI:10.1007/s10388-014-0434-8 · 0.74 Impact Factor
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    ABSTRACT: Background Post-esophagectomy complications have an extremely poor prognosis. Recently, polymyxin B-direct hemoperfusion (PMX-DHP) therapy using a polymyxin B-immobilized fiber column was reported to be beneficial in gram-negative and/or gram-positive bacterial sepsis. The present retrospective study investigated the effectiveness and safety of PMX-DHP therapy in severe sepsis or septic shock after esophagectomy. Methods Fifteen severe sepsis or septic shock patients were included. Seven (four, pneumonia; two, anastomotic leakage; and one, reconstructed colon necrosis) patients received 2–5 h of PMX-DHP therapy (PMX-DHP therapy group), whereas 8 (three, pneumonia; three, anastomotic leakage; and two, gastric tube necrosis) received conventional therapy (control group). Results Length of stay in the intensive care unit (ICU) was significantly shorter in the PMX-DHP therapy group than in the conventional therapy group (P = 0.040). In the comparison of pre- and post-PMX-DHP therapy groups, the total Sequential Organ Failure Assessment (SOFA) score, respiratory system score, and P/F ratio improved (P = 0.0027, P = 0.025, and P = 0.0087, respectively) in the post-PMX-DHP therapy group. In the comparison of conventional and PMX-DHP therapy groups, the variations in the total SOFA score, respiratory system score, and P/F ratio improved (P = 0.019, P = 0.0063, and P = 0.0015, respectively) in the PMX-DHP therapy group. Moreover, the respiratory system score was lower (P = 0.0062) in the PMX-DHP therapy group at the time of discharge from the ICU. No adverse effects were observed during the course of PMX-DHP therapy. Conclusions PMX-DHP therapy was safe and effective in improving respiratory and general conditions of patients with severe sepsis and septic shock after esophagectomy and decreased the length of stay in the ICU.
    Esophagus 07/2014; 11(3):189-196. DOI:10.1007/s10388-014-0428-6 · 0.74 Impact Factor
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    ABSTRACT: Purpose: The purpose of this study was to establish a prognostic indicator based on preoperative plasma fibrinogen and serum albumin levels (FA score) in esophageal cancer patients and to compare the correlation with survival to that of the Glasgow prognostic score. Methods: Patient characteristics, clinicopathological factors, and preoperative biochemical markers (fibrinogen, albumin, and C-reactive protein) were investigated in esophageal cancer patients who underwent transthoracic esophagectomy. Pretreatment fibrinogen and albumin levels were reviewed in patients who received neoadjuvant treatment. Patients with elevated fibrinogen and decreased albumin levels were allocated a score of 2, those with only one of these abnormalities were allocated a score of 1, and those with neither of these abnormalities were allocated a score of 0. The fibrinogen cut-off value was defined as 350 mg/dL according to our previous report, and the albumin cut-off value was defined as the lower quartile. Results: Among 199 consecutive patients, the interquartile range of preoperative albumin was 3.8-4.3 g/dL and the cut-off value was 3.8 g/dL. Thus, 108 (54 %), 68 (34 %), and 23 (12 %) patients had an FA score of 0, 1, and 2. The patients with a high preoperative FA score showed considerably shorter disease-free survival (DFS) and overall survival (OS). Multivariate analysis showed that pretreatment stage and preoperative FA score were independently associated with postoperative DFS and OS. Conclusions: Preoperative FA score was significantly associated with postoperative survival in esophageal cancer patients, and the prognostic value is currently being validated in a prospective multicenter cohort study.
    Annals of Surgical Oncology 06/2014; 22(1). DOI:10.1245/s10434-014-3857-5 · 3.93 Impact Factor
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    ABSTRACT: Intra-abdominal desmoid tumors are rare and most often occur in patients with a history of familial adenomatous polyposis, surgery, or pregnancy. We report a case of an intra-abdominal desmoid tumor mimicking the recurrence of gastric cancer. A 57-year-old male had undergone distal gastrectomy for advanced gastric cancer. Serum levels of carcinoembryonic antigen were found to be elevated 27 months after surgery. Computed tomography revealed a 15-mm mass in the mesentery of the transverse colon. In addition, radiotracer fluorodeoxyglucose uptake of the tumor was detected by positron emission tomography. The patient was diagnosed with gastric cancer recurrence, and chemotherapy consisting of cisplatin and S-1 was commenced. After five courses of chemotherapy, although no significant clinical response was seen, no new lesions were seen either. Thus, a curative resection of the recurrent tumor seemed possible, which was successfully performed. Histological examination of the resected specimen revealed spindle-shaped tumor cells with collagen fiber progression; no cancer cells were detected. The tumor was diagnosed as an intra-abdominal desmoid tumor. We report a rare case of an intra-abdominal desmoid tumor that mimicked a recurrent tumor arising from gastric cancer. In patients with history of surgery for intra-abdominal malignancies, it may be difficult to distinguish the recurrence of malignancy from desmoid tumors but the possibility of desmoid tumors must be considered in the differential diagnosis.
    World Journal of Surgical Oncology 05/2014; 12(1):146. DOI:10.1186/1477-7819-12-146 · 1.41 Impact Factor
  • Gastrointestinal Endoscopy 05/2014; 79(5):AB132-AB133. DOI:10.1016/j.gie.2014.02.082 · 5.37 Impact Factor
  • Gastrointestinal Endoscopy 05/2014; 79(5):AB136. DOI:10.1016/j.gie.2014.02.089 · 5.37 Impact Factor

Publication Stats

1k Citations
255.22 Total Impact Points


  • 2004–2015
    • Keio University
      • • Department of Surgery
      • • Center for Diagnostic and Therapeutic Endoscopy
      • • School of Medicine
      Edo, Tōkyō, Japan
  • 2014
    • Harvard Medical School
      Boston, Massachusetts, United States
  • 2003–2011
    • Kawasaki Municipal Hospital
      Kawasaki Si, Kanagawa, Japan
  • 2009
    • National Institute of Public Health
      Saitama, Saitama, Japan