Automatic detection of early gastric cancer in endoscopic images using a transferring convolutional neural network

Endoscopic image diagnosis assisted by machine learning is useful for reducing misdetection and interobserver variability. Although many results have been reported, few effective methods are available to automatically detect early gastric cancer. Early gastric cancer have poor morphological features, which implies that automatic detection methods can be extremely difficult to construct. In this study, we proposed a convolutional neural network-based automatic detection scheme to assist the diagnosis of early gastric cancer in endoscopic images. We performed transfer learning using two classes (cancer and normal) of image datasets that have detailed texture information on lesions derived from a small number of annotated images. The accuracy of our trained network was 87.6%, and the sensitivity and specificity were well balanced, which is important for future practical use. We also succeeded in presenting a candidate region of early gastric cancer as a heat map of unknown images. The detection accuracy was 82.8%. This means that our proposed scheme may offer substantial assistance to endoscopists in decision making.

Objective evaluation of the visibility of colorectal lesions using eye tracking

BACKGROUND AND AIM

To assess the visibility of colorectal lesions using blue laser imaging (BLI)-bright and linked-color imaging (LCI) with an eye-tracking system.

METHODS

Eleven endoscopists evaluated 90 images of 30 colorectal lesions. The lesions were randomly selected. Three images of each lesion comprised white light imaging (WLI), BLI-bright, and LCI in the same position. Participants gazed at the images, and their eye movements were tracked by the eye tracker. We analyzed whether the participants could detect the lesion and how long they took to detect the lesion. We assessed the miss rate and detection time among the imaging modalities.

RESULTS

One endoscopist was excluded, and 10 endoscopists were assessed. Overall, 12.6% of lesions were missed with WLI, 6.0% with BLI-bright, and 4.3% with LCI; the miss rate of BLI-bright and LCI was significantly lower than that of WLI (P < 0.01), with no significant difference between the former modalities (P = 0.54). Mean (± SD) detection times were 1.58 ± 1.60 s for WLI, 1.01 ± 1.21 s for BLI-bright, and 1.10 ± 1.16 s for LCI. Detection time for BLI-bright and LCI was significantly shorter than that for WLI (P < 0.0001), with no significant difference between the former modalities (P = 0.34). Regarding the miss rate and detection time between the expert and the non-experts, there was a significant difference with WLI but not with BLI-bright and LCI.

CONCLUSION

Blue laser imaging-bright and LCI improved the detection of colorectal lesions compared with WLI using an eye-tracking system.

Basic study of random sampling for compressed sensing using MRI simulator

INTRODUCTION

Magnetic resonance imaging (MRI) is a tomography technology that enables the depiction of anatomical structures with information about various features. Compressed sensing (CS) technology has recently been used for magnetic resonance image reconstruction from sparse information. Random sampling methods based on the various probability density function (PDF) are being developed to allow the efficient application of CS technology. Accurate numerical simulation is obviously important for the evaluation of the sampling method that are developed. In this study, the simulation method with MRI simulator and actual MRI scanner was carried out. Moreover, the difference between the result acquired from our simulation and basic one was revealed.

METHODS

We first examined a basic method using a 2D Shepp-Logan phantom. This method was only conducted with k-space data obtained from the 2D Fourier transform of the original image. Our method of numerical simulation was applied with the MRI simulator (Bloch Solver, MRI simulations Inc.), an actual MRI system (Vantage Titan 3T, Canon Medical Systems) and a phantom (CAGN-3.0T phantom, Kato Medience). The real and imaginary part of the k-space were acquired with the MRI simulator using a phase map that was imaged by the actual MRI scanner. Random sampling was performed with two types of PDF and image reconstruction was processed by projection onto convex sets (POCS). Hermitian symmetry is a point-symmetry respect to origin and each point located on the opposite side maintains a relation of complex conjugate. Thus, there is no need to acquire data that formed in point-symmetry with the data that had already been acquired. We used the gaussian random sampling method (GA) and a method that considered Hermitian symmetry (GH). The image quality was evaluated using the normalized root mean squared error (NRMSE).

RESULTS AND DISCUSSION

In the basic simulation, the average and standard deviation of NRMSE from GH was better than that from GA because consideration of the Hermitian symmetry enables the efficient acquisition of data. However, in our method of numerical simulation, the average and standard deviation of the NRMSE from GH was worse than that from GA. In this simulation method, the phase error was included in the real and imaginary part of the k-space; thus, the Hermitian symmetry cannot hold and the calculation error of reconstruction images from GH stood out.

CONCLUSION

The method of numerical simulation with the MRI simulator using a phase map was close to the actual conditions and was considered to be useful for the validation of new sampling methods. The random sampling method using GH is expected to be useful for the highly efficient acquisition of data under ideal conditions; however, more accurate phase correction is necessary to apply the actual measurement data.

Abstract CT024: Early safety from an open label Phase I study to evaluate the safety and efficacy of a telomerase-specific oncolytic adenovirus (OBP-301) with pembrolizumab in patients with advanced solid tumors. (EPOC1505)

Background: PD-1 blockade showed promising efficacy for broad type of cancer patients (pts), though objective response rates are very limited. The antitumor potential of oncolytic adenoviruses has been demonstrated in preclinical and clinical studies. In addition to the specific killing of cancer cells via oncolytic adenovirus, these agents prompt the immune system to stimulate an antitumor immune response. OBP-301 is an oncolytic adenovirus in which gene is modified to be able to selectively replicate in cancer cells by introducing human telomerase reverse transcriptase (hTERT) promotor. Further antitumor effect might be expected with an active activation of two different antitumor immunity by OBP-301 in combination with pembrolizumab. Therefore, we conducted phase I study to evaluate the safety and efficacy of OBP-301 with pembrolizumab.

Methods: The major eligibility criteria are pts with advanced or metastatic solid tumor not responded to or intolerant of standard chemotherapies, and with possibility of intratumoral injection. Phase Ia part was designed to determine the recommended dose in a “3+3” cohort-based dose escalation design of OBP-301 (1x1010VP on cohort 1, 1x1011VP on cohort 2 and 1x1012VP on cohort 3) with pembrolizumab (200mg/body q3w). OBP-301 is administered at day1, 15, and, 29 by intratumoral injection and pembrolizumab is administered at day 8 and thereafter every 3 weeks. Primary endpoint is dose limiting toxicity (DLT). Secondary endpoint is response rate, progression free survival, and incidence of adverse event. Phase Ib part was designated to evaluate the safety and efficacy of the recommended dose OBP-301 selected in phase Ia part in combination with pembrolizumab in 10 pts. Biomarker study was planned using paired samples of both tumor biopsy and blood. Clinical trial information: NCT03172819.

Results: The first patient was enrolled on 7 Dec 2017; the last patient in phase Ia part was enrolled on 12 Oct 2018. Nine DLT-evaluable pts were enrolled and treated in phase Ia part: median age was 59; 2/9 female; 8/9 esophageal squamous cell carcinoma, 1/9 gastric adenocarcinoma. No DLT was observed during the DLT evaluation period. The most common adverse events were fever (Gr.2: 2/9, Gr.1: 2/9), hepatic disorder (Gr.3: 1/9, Gr.1: 1/9), pleural effusion (Gr.1:1/9). Preliminary efficacy assessment of phase Ia by investigators’ judgment demonstrated 2 PRs of the 9 pts.

Conclusion: The combination of OBP-301 with pembrolizumab was well tolerated in tested doses. The recommended dose for phase Ib part is 1x1012VP (cohort 3), and additional 10 pts will be enrolled to obtain additional safety and efficacy data. Preliminary result of biomarker analyses using paired samples of both tumor biopsy and blood will be presented.

Citation Format: Takashi Kojima, Toshiyoshi Fujiwara, Yasuhiro Shirakawa, Keisuke Hori, Hiromi Ono, Masako Nakamoto, Nami Hirano, Masashi Wakabayashi, Shogo Nomura, Yosuke Togashi, Hiroyoshi Nishikawa, Akihiro Sato, Atushi Ohtsu, Toshihiko Doi. Early safety from an open label Phase I study to evaluate the safety and efficacy of a telomerase-specific oncolytic adenovirus (OBP-301) with pembrolizumab in patients with advanced solid tumors. (EPOC1505) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT024.

Long-term follow-up of custom cross-pin fixation of 56 tumour endoprosthesis stems: a single-institution experience

AIMS

Aseptic loosening is a major cause of failure in cemented endoprosthetic reconstructions. This paper presents the long-term outcomes of a custom-designed cross-pin fixation construct designed to minimize rotational stress and subsequent aseptic loosening in selected patients. The paper will also examine the long-term survivorship and modes of failure when using this technique.

PATIENTS AND METHODS

A review of 658 consecutive, prospectively collected cemented endoprosthetic reconstructions for oncological diagnoses at a single centre between 1980 and 2017 was performed. A total of 51 patients were identified with 56 endoprosthetic implants with cross-pin fixation, 21 of which were implanted following primary resection of tumour. Locations included distal femoral (n = 36), proximal femoral (n = 7), intercalary (n = 6), proximal humeral (n = 3), proximal tibial (n = 3), and distal humeral (n = 1).

RESULTS

The median follow-up was 132 months (interquartile range (IQR) 44 to 189). In all, 20 stems required revision: eight for infection, five for structural failure, five for aseptic loosening, and two for tumour progression. Mechanical survivorship at five, ten, and 15 years was 84%, 78%, and 78%, respectively. Mechanical failure rate varied by location, with no mechanical failures of proximal femoral constructs and distal femoral survivorship of 82%, 77%, and 77% at five, ten, and 15 years. The survivorship of primary constructs at five years was 74%, with no failure after 40 months, while the survivorship for revision constructs was 89%, 80%, and 80% at five, ten, and 15 years.

CONCLUSION

The rate of mechanical survivorship in our series is similar to those reported for other methods of reconstruction for short diaphyseal segments, such as compressive osseointegration. The mechanical failure rate differed by location, while there was no substantial difference in long-term survival between primary and revision reconstructions. Overall, custom cross-pin fixation is a viable option for endoprosthetic reconstruction of short metaphyseal segments with an acceptable rate of mechanical failure. Cite this article: Bone Joint J 2019;101-B:724-731.

Human epidermal growth factor receptor 2-, epidermal growth factor receptor-, and mesenchymal epithelial transition factor-positive sites of gastric cancer using surgical samples

BACKGROUND

Receptor tyrosine kinases (RTKs) play critical roles in gastric cancer (GC) progression and are potential targets for novel molecular-targeted agents or photo-immunotherapies. During patient selection, targeted biopsy is the first step. However, heterogeneous expression of RTKs based on the macroscopic appearance in GC has not been extensively addressed. Accordingly, in this study, we evaluated differences in RTK expression associated with macroscopic appearance in GC.

METHODS

In total, 375 consecutive patients who had undergone gastrectomy at the National Cancer Center Hospital East and who had histologically proven adenocarcinoma, available archived tumor sample, and no history of chemotherapy were enrolled in this study. For these cases, tissue microarray (TMA) samples were examined using immunohistochemistry (IHC). Based on the results of IHC, cases were selected for detailed examination. We re-evaluated IHC scores in more than three tumor blocks per case and comparatively evaluated differences in IHC expression in RTKs between the mucosal portion (MuP) and invasive portion (InP).

RESULTS

Human epidermal growth factor receptor 2 (HER2)-, epidermal growth factor receptor (EGFR)-, and mesenchymal epithelial transition factor (c-MET)-positive rates were 6, 9, and 20%, respectively. Twenty-two cases were then analyzed to assess differences in IHC expression levels in the same lesion. Concordance rates of positive staining of HER2, EGFR, and MET between MuP and whole tumor were 100, 40, and 56% and those with InP were 46, 100, and 56%.

CONCLUSIONS

To avoid underestimating expression status, biopsies must be taken from MuP for HER2, InP for EGFR, and both proportions for c-MET.

Technical feasibility of endoscopic submucosal dissection for local failure after chemoradiotherapy or radiotherapy for esophageal squamous cell carcinoma

BACKGROUND AND AIMS

Salvage endoscopic submucosal dissection (ESD) after chemoradiotherapy can be technically difficult as a result of radiation-induced fibrosis. We aimed to evaluate the technical feasibility of ESD for local failure after chemoradiotherapy for esophageal squamous cell carcinoma (ESCC) and for other primary lesions within the irradiation field.

METHODS

Consecutive patients treated with ESD for superficial ESCC between December 2009 and May 2017 were investigated retrospectively and stratified into group A (33 patients, 35 lesions; local failure at the primary site after chemoradiotherapy), group B (25 patients, 34 lesions; second primary lesions within the irradiation field), and group C (550 patients, 596 lesions; radiotherapy-naïve superficial ESCC). We evaluated procedural success rate, en bloc resection rate, 1-year local relapse-free survival (LRFS) rate, procedure time, and incidence of major adverse events.

RESULTS

The rates of procedural success and en bloc resection, respectively, were significantly lower in group A (89%, 86%) than in groups B (100%, 100%) and C (100%, 98%). The 1-year LRFS rates were 86%, 100%, and 99% in groups A, B, and C, respectively, and significantly lower in group A than in group C. Serious adverse events including perforation were not observed in groups A and B; perforation occurred only in group C (2.8%).

CONCLUSIONS

ESD is technically feasible in patients with local failure, especially as initial salvage treatment and as treatment for second primary lesions within the irradiation field.

Salvage endoscopic resection (ER) after chemoradiotherapy for esophageal squamous cell carcinoma: What are the risk factors for recurrence after salvage ER?

BACKGROUND AND AIM

Salvage endoscopic resection (ER) is among the curative treatments for superficial local failure after chemoradiotherapy (CRT) for esophageal squamous cell carcinoma (ESCC). The present study aimed to clarify risk factors for recurrence after salvage ER.

METHODS

This study enrolled consecutive ESCC patients treated with salvage ER for local failure after CRT between 1998 and 2013. Recurrences after salvage ER included locoregional recurrences and distant metastases. Multivariate analysis was carried out on clinicopathological parameters to identify risk factors for post-salvage ER recurrence.

RESULTS

Of the 72 patients enrolled in this study, 37/8/23/4 patients had been staged before CRT as cT1/T2/T3/T4 and 44/28 patients as cN0/N1, respectively, and local failures detected before salvage ER were residual lesions after CRT in 19 and local recurrences in 53 patients. Resected specimens were classified as pT1a (M) in 45 and pT1b (SM) in 27 patients. During the median 45-month follow up (range, 3-175 months) after salvage ER, 27 (38%) patients developed recurrence with a 3-year recurrence-free survival rate of 48.9% (95% confidence interval [CI], 36.5-60.3). Multivariate analysis showed that residual lesions after CRT (HR, 2.55; 95% CI, 1.32-4.94) and lesions with a submucosal tumor (SMT)-like appearance before salvage ER (HR, 2.08; 95% CI, 1.04-4.18) were significantly associated with post-salvage ER recurrence.

CONCLUSIONS

Clinical findings (e.g. residual tumors found immediately after CRT and macroscopic SMT-like appearance before salvage ER) were shown to be significant risk factors for post-salvage ER recurrence.

Combustion Study of Different Transitional Metal Oxide based on AN/MgAl Composites Gas Generators

Ammonium nitrate (AN)-based composite gas generator have attracted a considerable amount of attention because of the clean burning nature of AN as an oxidizer. However, ammonium nitrate-based gas generator has several major problems, namely, poor ignitability, a low burning rate, low energy, and high hygroscopicity. The addition of different transitional metal oxides and MgAl mechanical alloyed proved to be effective in improving the burning characteristics of AN-based gas generator. In this research work, combustion study of different transition metal oxide based on AN/MgAl composites gas generators was studied. Gas generators were combusted at the pressure of 1 MPa, 3 MPa and 5 MPa in the combustion chamber and the burning rates were determined. It was stated that the addition of metal oxides into the composition of the gas generators improves ignition at low pressure and increases the burning rate. The use of the mechanical MgAl alloys as a fuel allowed the ignition of the gas generator at a lower temperature. The method of thermogravimetric/differential thermal analyzer (TG/DTA) was used to investigate the effect of metal oxides addition on the AN/MgAl-based gas generators thermal decomposition characteristics.

Visual assessment of colorectal flat and depressed lesions by using narrow band imaging

BACKGROUND AND STUDY AIMS

 Visual assessment of laterally spreading tumors non-granular type (LST-NG) and depressed lesions by narrow band imaging (NBI) without magnification has not been studied. We investigated the role of non-magnifying NBI in detecting LST-NG and type IIc lesions on colonoscopy.

PATIENTS AND METHODS

 This retrospective study examined consecutive patients diagnosed as having LST-NG and/or type IIc lesions in our hospital between August 2011 and July 2013. These lesions were classified as "Brownish area (BA)," "Brown only in the margins (O-ring sign)," "Same color as the normal mucosa (SC)," and "Whitish area (WA)" based on their appearance on non-magnifying NBI, and their appearance were compared with their histopathological findings.

RESULTS

 A total of 18 type IIc and 180 LST-NG lesions were analyzed. Among the type IIc lesions, 5 (28 %), 12 (67 %), and 1 (5 %) were classified as BA, O-ring sign, and SC, respectively. Among the LST-NG lesions, 126 (70 %), 26 (14 %), and 28 lesions (16 %) were classified as BA, O-ring sign, and SC, respectively. The IIc lesions were found to have 1 lesion (20 %) with high-grade dysplasia (HGD) in the BA, and 2 lesions (17 %) with invasive cancer (IC) in the O-ring sign group. Among the LST-NG lesions, 27 (21 %) were found to have IC and 49 (39 %), HGD in the BA group; 8 lesions (31 %) had IC and 4 (15 %) had HGD in the O-ring sign group; and 1 lesion (4 %) had IC and 4 (14 %) had HGD in the SC group.

CONCLUSIONS

 Most flat and depressed colorectal lesions were seen on non-magnifying NBI as brown lesions with the exception of some flat lesions that were indistinguishable in color from the adjacent normal mucosa. Some of these flat lesions were also found to have HGD or IC.

Combustion Characteristics of HAN-based Green Propellant Assisted with Nanoporous Active Carbons

Combustion of hydroxylammonium nitrate (95 wt.% HAN) ‒ water solution in presence of high specific surface area activated carbons is investigated in a constant-pressure bomb within the pressure range of 1‒6 MPa. The linear burning rate increased for the system of HAN admixed with activated carbons compared to those of the HAN alone. Moreover, the thermal decomposition of HAN (95 wt.%) ‒ water solution spiked with activated carbons was assessed by DTA – TG method. In the presence of activated carbons, the ability to trigger the decomposition at a lower temperature (86 °C vs 185 °C) was observed. The volatile products formed in the course of thermal decomposition of HAN, spiked with activated carbons were characterized by electron ionization mass spectrometry analysis. Primary products of HAN decomposition: m/z = 33 (NH2OH) and m/z = 63 (HNO3), which are further responsible for the formation of secondary products such as N2O, NO, HNO2, NO2, O2 etc. Significant reduction of NOx emissions during thermal decomposition of HAN (95 wt.%) ‒ water solution was observed (ca. 30%) in presence of activated carbons.

Endoscopic treatment outcomes of laterally spreading tumors with a skirt (with video)

BACKGROUND AND AIMS

A "skirt" is a slightly elevated flat lesion with wide pits occasionally observed at the margin of laterally spreading tumors (LSTs). However, the endoscopic treatment outcomes of LSTs with skirts have not been clarified. The aim of this study was to evaluate the endoscopic treatment outcomes of LSTs with skirts.

METHODS

Between February 2006 and March 2014, 996 LSTs were retrospectively examined to assess the clinicopathologic characteristics, procedure time, en bloc resection rate, R0 resection rate, adverse events, and local recurrence rate of endoscopic submucosal dissection (ESD) and of endoscopic resection.

RESULTS

Endoscopic treatment was performed in 35 cases of LSTs with skirts (ratio of ESD to endoscopic piecemeal mucosal resection [EPMR], 32:3) and 961 cases of LSTs without skirts (ratio of ESD to EMR to EPMR to polypectomy, 381:275:114:191). LSTs with a skirt were associated with a significantly higher recurrence rate (P < .01). In both ESD and EPMR, LSTs with a skirt were associated with a higher recurrence rate when compared with LSTs without a skirt (odds ratio, 12.7; P = .032, and odds ratio, 12.3; P = .061, respectively). Multivariate analysis demonstrated that the presence of the skirt and piecemeal resection were significant predictors of local recurrence.

CONCLUSIONS

LSTs with skirts had a significantly higher local recurrence rate after endoscopic treatment compared with LSTs without skirts, especially after EPMR. Therefore, ESD should be recommended as an endoscopic treatment for LSTs with skirts to minimize local recurrence.

Evaluation of the bleeding risk with various antithrombotic therapies after gastric endoscopic submucosal dissection

BACKGROUND AND STUDY AIMS

Patients receiving antithrombotic drugs have a higher risk of postoperative bleeding and thromboembolic events related to endoscopic procedures. The aim of this study was to evaluate the relationship between various antithrombotic therapies and bleeding after gastric endoscopic submucosal dissection (ESD) (post-ESD bleeding).

PATIENTS AND METHODS

 Among 529 consecutive gastric ESD procedures (483 patients with 579 legions), 100 patients with 121 lesions who underwent 108 procedures were on antithrombotic therapy (group A) and 382 patients with 458 lesions who underwent 421 procedures were not on antithrombotic therapy (group B). The ratio of post-ESD bleeding between the two groups and the bleeding risk related to various antithrombotic therapies were investigated.

RESULTS

Postoperative bleeding was more frequent in group A (11.1 %) than in group B (3.3 %). No thromboembolic events were reported in either group. Further investigation of antithrombotic therapies in group A demonstrated that various combinations of antithrombotic agents and heparin replacement were associated with a higher ratio of post-ESD bleeding. Multivariate analyses revealed that dual antiplatelet therapy (odds ratio [OR] 10.9, 95 % confidence interval [CI] 2.1 - 49.5; P  = 0.005) and heparin replacement (OR 34.4, 95 %CI 9.4 - 133.2; P  < 0.001) were associated with the increased risk of post-ESD bleeding. In patients on antiplatelet therapy, post-ESD bleeding tended to occur in the early postoperative period compared with patients on anticoagulant therapy.

CONCLUSIONS

 It is necessary to be cautious regarding post-ESD bleeding in patients requiring antithrombotic therapy, especially patients receiving dual antiplatelet therapy and heparin replacement. A further prospective study with a large sample will be needed to confirm these findings.

Alcohol abstinence and risk assessment for second esophageal cancer in Japanese men after mucosectomy for early esophageal cancer

BACKGROUND

Alcohol consumption combined with inactive aldehyde dehydrogenase-2 (ALDH2) and the presence of multiple esophageal Lugol-voiding lesions (LVLs; dysplasia) are strong predictors for multiple development of esophageal squamous cell carcinoma (ESCC) in East Asians. We invented a health risk appraisal (HRA) model for predicting the risk of ESCC based on drinking, smoking, dietary habits, and alcohol flushing, i.e., past or present facial flushing after drinking a glass of beer, a surrogate marker for inactive ALDH2.

METHODS

Prospective follow-up examinations (median follow-up time, 50.3 months) were performed in 278 Japanese men after endoscopic mucosectomy for early ESCC (UMIN Clinical Trials Registry ID: UMIN000001676).

RESULTS

Sixty-four subjects developed metachronous ESCC. A receiver operating characteristic curve showed that HRA scores ≥12 best predicted the development of metachronous ESCC. The ESCC detection rate per 100 person-years was 9.8 in the high-HRA-score group (n = 104) and 4.5 in the low-HRA-score group (n = 174), and the risk of development of metachronous ESCC was higher in the high-HRA-score group than in the low-HRA-score group (adjusted hazard ratio: 2.00 [95% CI: 1.12-3.30]). Multiple LVLs was a very strong predictor of the development of metachronous SCC, but high HRA scores predicted it independently. The cumulative incidences of metachronous ESCC decreased after drinking cessation in the high-HRA-score drinker group (adjusted hazard ratio: 0.37 [0.14-0.97]).

CONCLUSIONS

Both the HRA model that included alcohol flushing and the multiple LVL grade predicted the development of metachronous ESCC in Japanese men after endoscopic mucosectomy for ESCC. Drinking cessation in the high-HRA-score drinker group reduced the rate of metachronous ESCC.

Actual Status of Involvement of Helicobacter pylori Infection That Developed Gastric Cancer from Group A of ABC (D) Stratification - Study of Early Gastric Cancer Cases That Underwent Endoscopic Submucosal Dissection

BACKGROUND/AIMS

Patients who are Helicobacter pylori antibody negative and have normal pepsinogen (PG) levels (group A of ABC (D) stratification) are considered unlikely to develop gastric cancer. This study aimed to clarify the involvement (uninfection, present infection or previous infection) of H. pylori in group A patients with early gastric cancer who underwent endoscopic submucosal dissection (ESD) by examining their background gastric mucosa endoscopically and histologically.

METHODS

This study included 166 patients with gastric cancer who were treated by ESD. Patients were classified according to PG levels and H. pylori antibody titers. Three biopsies (greater curvature of the antrum, lesser curvature of the middle corpus and greater curvature of the middle corpus) from group A were histologically analyzed and compared with those of groups B, C, D and after eradication).

RESULTS

In group A (34 patients), 32 patients had endoscopic atrophy (group A'). Histological neutrophil activity, chronic inflammation and atrophy scores were lower in group A' than in other groups. Group A' scores were similar to those of the after eradication group.

CONCLUSION

Most of the group A patients with early gastric cancer were not uninfected with H. pylori, but had previous infections, thus carrying carcinogenic risk.