A successful case of transarterial chemoembolization for hyperprogressive disease induced by immunotherapy in a patient with unresectable hepatocellular carcinoma.

A fraction of patients with hepatocellular carcinoma (HCC) shows unexpected rapid tumor growth, called hyperprogressive disease (HPD) after the initiation of atezolizumab and bevacizumab (ATZ + BEV). However, little information is available concerning salvage therapy after HPD and the possibility of resuming ATZ + BEV. A 60-year-old woman with unresectable HCCs was treated with transarterial chemoembolization (TACE) and followed by lenvatinib, which showed an unsatisfactory result. Multiple HCCs had been noted in both lobes just before ATZ + BEV treatment. After the initiation of ATZ + BEV, a tumor in the left lobe grew rapidly. The tumor growth kinetics ratio and tumor growth rate ratio of the rapidly growing lesion were 3.76 and 2.02, respectively. Thyroid dysfunction was noted after the initiation of ATZ + BEV. The neutrophil/lymphocyte ratios just before and at 3 weeks after the first ATZ + BEV treatment were 3.89 and 3.5, respectively. Drug-eluting bead (DEB)-TACE using cisplatin was performed for the rapidly growing tumor, which was effective for the targeted HCC in the left lobe as well as multiple HCCs in the right lobe. We were able to resume and continue ATZ + BEV without HPD, which was effective for HCC. We considered that DEB-TACE is an option for treating HPD.

Utility of FibroScan-based scoring systems to narrow the risk group of nonalcoholic fatty liver disease with comorbidities.

BACKGROUND: Vibration-controlled transient elastography (VCTE) is proposed as a second step of examination to assess liver fibrosis in patients with nonalcoholic fatty liver disease (NAFLD) after triaging by the fibrosis-4 (FIB-4) index. Recently, VCTE-based scoring systems, including FibroScan-AST (FAST), Agile 3+, and Agile 4, emerged to determine the status of NAFLD. However, the significance of these scoring systems remains unknown in narrowing the high-risk group of NAFLD patients with comorbidities, including hepatocellular carcinoma (HCC) and esophagogastric varices (EGV). AIM: To clarify the significance of VCTE-based scoring systems to narrow the high-risk group of NAFLD patients with comorbidities. METHODS: We performed a cross-sectional study to investigate the usefulness of VCTE-based scoring systems and other fibrosis markers to narrow the high-risk group of patients with NAFLD. FIB-4 index was used for the first triage. Risk groups of FAST, Agile 3+, and Agile 4 were stratified according to the published data. Among the 191 patients with NAFLD, there were 26 (14%) and 25 patients (13%) with HCC and EGV, respectively. RESULTS: When 1.3 was used as a cutoff value, the FIB-4 index narrowed the risk group to 120 patients, in which all patients with HCC and/or EGV were included. High risk group of Agile 3+ could subsequently narrow the risk group. The prevalence of HCC and EGV at this step were 33% (26/80) and 31% (25/80), respectively. In further narrowing of EGV, Agile 4 aggregated the patients with EGV into 43 patients, of whom 23 (53%) had EGV. FAST failed to narrow the risk group of patients with comorbidities. When 2.6 was used as a cutoff value of the FIB-4 index, three patients with HCC and two patients with EGV were missed at the first triage. CONCLUSION: Agile 3+ and Agile 4 are useful to narrow the NAFLD patient group, in which patients may have HCC and/or EGV.

Conventional Therapies Do Not Prolong the Prognosis of Hepatocellular Carcinoma Patients with Extrahepatic Metastases under Receiving of Tyrosine Kinase Inhibitors.

BACKGROUND: Conventional therapies, including chemoembolization and radiation therapy, have been expected to prolong the prognosis of hepatocellular carcinoma (HCC) patients with extrahepatic metastases, which remains poor. However, little information is available on the efficacy of conventional therapies for such patients under tyrosine kinase inhibitor (TKI) treatment. METHODS: We retrospectively investigated 127 HCC patients with extrahepatic metastases, who were divided into the non-TKI (conventional therapies) and TKI groups and further subdivided into the TKI alone and TKI plus conventional therapies groups. Conventional therapies included transcatheter arterial chemoembolization, cisplatin-based chemotherapy, radiation, surgery, and UFT, an oral chemotherapeutic agent. RESULTS: The median of the overall survival (OS) of the 127 patients with extrahepatic metastases was 7.0 months. Meanwhile, the median OS of the TKI and non-TKI groups was 12.1 and 4.1 months, respectively. Imitating TKI after diagnosing metastases promoted a favorable increase in OS. Among the TKI group, the median OS in the TKI alone group was 8.9 months. TKI plus conventional therapies promoted no improvement in OS after adjusting for the patients' background data. CONCLUSION: TKI promoted a better OS in HCC patients with extrahepatic metastases compared to conventional therapies. However, TKI plus conventional therapies promoted no improvement in the prognosis of such patients.

Efficacy and safety of glecaprevir and pibrentasvir combination therapy in old-aged patients with chronic hepatitis C virus infection.

Objective: Combination therapy with glecaprevir and pibrentasvir (G/P) has been shown to provide a sustained virologic response (SVR) rate of >97% in patients with chronic hepatitis C virus (HCV) infection in the first published real-world Japanese data. However, a recently published study showed that the treatment was often discontinued in patients ≥75 years old, resulting in low SVR in intention-to-treat (ITT) analysis. Thus, our aim was to evaluate real-world data for G/P therapy in patients ≥75 years of age, the population density of which is high in "rural" regions. Patients and Methods: We conducted a multicenter study to assess the efficacy and safety of G/P therapy for chronic HCV infection, in the North Kanto area in Japan. Results: Of the 308 patients enrolled, 294 (95.5%) completed the treatment according to the protocol. In ITT and per-protocol analyses, the overall SVR12 rate was 97.1% and 99.7%, respectively. The old-aged patients group consisted of 59 participants, 56 of whom (94.9%) completed the scheduled protocol. Although old-aged patients tended to have non-SVR factors such as liver cirrhosis, history of HCC, and prior DAA therapies, the SVR12 rates in old-aged patients were 98.3% and 100% in the ITT and PP analyses, respectively. Of 308 patients enrolled, adverse events were observed in 74 patients (24.0%), with grade ≥3 events in 8 patients (2.6%). There was no significant difference in any grade and grade ≥3 adverse events between the old-aged group and the rest of the study participants. Only one patient discontinued the treatment because of adverse events. Conclusion: G/P therapy is effective and safe for old-aged patients.

Successful treatment of hepatocellular carcinoma by laparoscopic radiofrequency ablation in a patient with hemophilia A.

Percutaneous radiofrequency ablation (RFA) is a good indication for hepatocellular carcinoma (HCC) in cases involving ≦ 3 tumors of ≦ 30 mm in size, many hepatologists are hesitant to perform the procedure for patients with hemorrhagic disorders. We herein report the successful treatment of HCC by laparoscopic RFA in a patient with hemophilia A. A 48-year-old man with moderate form of hemophilia A had a single HCC at segment 8. To perform laparoscopic RFA safely, recombinant factor VIII (rFVIII) was administered to maintain factor VIII activity (FVIII:C) > 80% on the operation day and > 40% for 6 days after the operation in accordance with the guidelines. A total of 23,000 units of rFVIII was used. Laparoscopic RFA was completed with an operation time of 105 min and < 10 mL of blood loss. As a result, blood transfusion was not required. At 2 years after the initial treatment, HCC recurred at segment 7. Under rFVIII supplementation, we performed a second laparoscopic RFA without any events. Although partial hepatectomy is the main procedure used to treat HCC in patients with hemophilia, we could reduce in total use of rFVIII, blood and operation time by laparoscopic RFA compared with those in partial hepatectomy.

Acute Liver Failure Caused by the Transmission of Hepatitis B Virus from the Spouse after 38 Years of Marriage.

A 65-year-old man presented with acute liver failure and grade IV coma caused by hepatitis B virus (HBV) infection in 2017. The patient died on day 12 from the disease onset. The HBV isolated from the patient was genotype/subgenotype B/B1 and had multiple genomic mutations. The patient's wife was hepatitis B surface antigen (HBsAg)-positive when she delivered her first daughter in 1979. The HBV isolates of the patient and the wife shared 100% similarity over the entire genome. Because the patient's HBsAg value had been negative one year earlier, we considered the source of HBV transmission to be his wife.

Usefulness of Gd-EOB-DTPA-enhanced MRI for evaluating the potential for early development of hepatocellular carcinoma after HCV eradication by direct-acting antiviral treatment.

Objective: The development of hepatocellular carcinoma (HCC) is not uncommon in patients who achieve eradication of the hepatitis C virus through direct-acting antiviral (DAA) treatment. The aim of this study was to identify the patients at high risk for novel HCC development after a sustained virologic response (SVR) by DAA treatment. Patients and Methods: A total of 518 patients with no history of HCC treatment and who achieved SVR by DAA treatment were evaluated retrospectively. The correlations between HCC development and the patients' characteristics were evaluated. For patients who underwent gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) or dynamic contrast-enhanced computed tomography, the relationship between the imaging findings and subsequent HCC development was also assessed. Results: HCC developed newly in 22 patients, and the 1-year and 3-year cumulative HCC rates were 2.0% and 8.5%, respectively. In multivariate analysis, a FIB-4 index >4.0 and a post-treatment α-fetoprotein >4.0 ng/ml were significant risk factors for HCC. In 26 of 118 patients who underwent an MRI before DAA treatment, a non-hypervascular hypo-intense nodule was seen in the hepatobiliary phase, and in 6 of 182 patients who underwent a CT, a non-hypervascular hypo-enhanced nodule was seen in the delayed phase. The sensitivity and specificity of the MRI-positive findings for the subsequent development of HCC were 0.92 and 0.87, respectively, and those of the CT were 0.40 and 0.99, respectively. In multivariate analysis of patients who underwent an MRI, a non-hypervascular hypo-intense nodule was the only factor that was significantly related to HCC development (HR 32.4, p = 0.001). Conclusion: Gd-EOB-DTPA-enhanced MRI was found to be reliable for risk evaluation of subsequent HCC development in patients after SVR by DAA treatment. Patients with a non-hypervascular hypo-intense nodule need more careful observation for incident HCC.

Full-genome characterization of the RIVM-HAV16-090-like hepatitis A virus strains recovered from Japanese men who have sex with men, with sporadic acute hepatitis A.

AIM: The major transmission mode of hepatitis A virus (HAV) in Japan is the fecal-oral route by contaminated foods. In contrast, HAV infection is well documented as a sexually transmitted disease in Europe and North America. The present study was undertaken to determine the full-genome sequence of HAV and trace the transmission route of HAV in Japanese men who have sex with men (MSM). METHODS: In 2018, we encountered three Japanese MSM with acute hepatitis A co-infected with HIV for 4-12 years. Serum samples obtained from these patients were used for HAV full-genome analyses. RESULTS: Isolated HAV strains were segregated into subgenotype IA. The three HAV strains shared 100% identity within the 481-nucleotide partial sequence. The entire nucleotide sequence showed that the three strains were 99.97% similar to each other with only two nucleotide substitutions. At the amino acid level, the three strains differed from each other by only one or two amino acids. All three strains obtained in the present study were >99.6% identical to the 66 reported strains isolated from Taiwan and European countries during 2015-2017. In addition, these 66 strains include the RIVM-HAV16-090 (EuroPride) strain, which has been involved in HAV outbreaks among MSM worldwide. CONCLUSIONS: We determined for the first time the full-genome sequence of HAV isolated from Japanese MSM with acute hepatitis A and found that the strains were identical to those from MSM worldwide. Thus, these HAV strains were imported to Japan from foreign countries through MSM.

The successful treatment of hepatocellular carcinoma arising from congenital hepatic fibrosis using radiofrequency ablation under laparoscopy.

Congenital hepatic fibrosis (CHF), a fibropolycystic disease, is characterized by bile duct malformation, periportal fibrosis, and renal polycystic disease. Although cholangiocellular carcinoma is the primary tumor arising from fibropolycystic diseases, hepatocellular carcinoma (HCC) is extremely rare. In addition, no algorism for determining the optimum HCC treatment has yet been available in cases of fibropolycystic disease due to variations in the background liver and renal conditions. We herein report a patient with HCC arising from CHF that was successfully treated using radiofrequency ablation (RFA) under laparoscopic assistance. A 37-year-old man with CHF was admitted to our hospital for treatment of HCC in 2014. Imaging revealed HCC located in hepatic segments II and VIII with diameters of 28 and 24 mm, respectively. There had been no histories of recurrent cholangitis or renal failure after when CHF was diagnosed in 2003. In addition, esophageal varices were well controlled. We achieved sufficient ablation using a bipolar ablation system without any complications. The post-operative course was uneventful, and the patient was free from HCC for 4 years. Thus, locoregional therapy, including RFA, is acceptable for the treatment of HCC arising from CHF when the background liver and kidney are preserved.

No Regional Disparities in Sofosbuvir Plus Ribavirin Therapy for HCV Genotype 2 Infection in Tochigi Prefecture and Its Vicinity.

Objective Regional disparities were observed in the outcomes of interferon (IFN)-based therapy for chronic hepatitis C virus (HCV) infection in a Japanese nationwide study. However, whether or not these regional disparities are observed in the outcomes of direct-acting antiviral drugs, including sofosbuvir (SOF) plus ribavirin (RBV) therapy, remains unclear. Methods We conducted a multicenter study to assess the efficacy of SOF plus RBV therapy for HCV genotype 2 infection in Tochigi Prefecture and its vicinity, in which IFN-based therapy yielded a low sustained virologic response (SVR) rate. In addition, we divided Tochigi Prefecture into six regions to examine regional disparities in the SVR. Patients We enrolled patients with chronic HCV genotype 2 infection. Results Of the 583 patients enrolled, 569 (97.6%) completed the treatment, and 566 (97.1%) also complied with post-treatment follow-up for 12 weeks. The overall SVR12 rate was 96.1% by per protocol and 93.7% by intention-to-treat analyses. No marked differences were observed in the SVR12 between subjects ≥65 and <65 years of age. Although large gaps were observed in the characteristics of patients and accessibility to medical resources, there was no significant difference in the SVR12 rate among the six regions in Tochigi Prefecture. Conclusion SOF plus RBV therapy was effective for HCV genotype 2 infection in an area where IFN-based therapy had previously shown unsatisfactory results. In addition, no regional disparities in the SVR12 were observed in Tochigi Prefecture.

Ezetimibe suppresses development of liver tumors by inhibiting angiogenesis in mice fed a high-fat diet.

Nonalcoholic steatohepatitis (NASH) is a common cause of liver cirrhosis and hepatocellular carcinoma (HCC). However, effective therapeutic strategies for preventing and treating NASH-mediated liver cirrhosis and HCC are lacking. Cholesterol is closely associated with vascular endothelial growth factor (VEGF), a key factor that promotes HCC. Recent reports have demonstrated that statins could prevent HCC development. In contrast, we have little information on ezetimibe, an inhibitor of cholesterol absorption, in regards to the prevention of NASH-related liver cirrhosis and HCC. In the present study, a steatohepatitis-related HCC model, hepatocyte-specific phosphatase and tensin homolog (Pten)-deficient (PtenΔhep ) mice were fed a high-fat (HF) diet with/without ezetimibe. In the standard-diet group, ezetimibe did not reduce the development of liver tumors in PtenΔhep mice, in which the increase of serum cholesterol levels was mild. Feeding of a HF diet increased serum cholesterol levels markedly and subsequently increased serum levels of VEGF, a crucial component of angiogenesis. The HF diet increased the number of VEGF-positive cells and vascular endothelial cells in the tumors of PtenΔhep mice. Kupffer cells, macrophages in the liver, increased VEGF expression in response to fat overload. Ezetimibe treatment lowered cholesterol levels and these angiogenetic processes. As a result, ezetimibe also suppressed inflammation, liver fibrosis and tumor growth in PtenΔhep mice on the HF diet. Tumor cells were highly proliferative with HF-diet feeding, which was inhibited by ezetimibe. In conclusion, ezetimibe suppressed development of liver tumors by inhibiting angiogenesis in PtenΔhep mice with hypercholesterolemia.

A 79-year-old Woman with Acute Hepatitis B Caused by the Infection of Subgenotype D1 Hepatitis B Virus in Japan: A Case Study.

A 79-year-old Japanese woman was diagnosed with acute hepatitis B based on laboratory tests showing positivity for IgM-class antibody against hepatitis B virus (HBV) core and hepatitis B surface antigen (HBsAg) as well as elevated transaminases. A phylogenetic analysis revealed that the HBV strain obtained from the patient belonged to genotype D/subgenotype D1, similar to strains circulating in foreign countries but different from those in Japan. The clinical course was favorable. HBsAg became negative within 10 weeks after the onset. To our knowledge, this is the first report of acute hepatitis B caused by subgenotype D1 HBV in Japan.

The rendezvous technique involving insertion of a guidewire in a percutaneous transhepatic gallbladder drainage tube for biliary access in a case of difficult biliary cannulation.

Endoscopic retrograde cholangiopancreatography (ERCP) is a diagnostic method and treatment approach for biliary diseases. However, biliary cannulation can be difficult in some cases. We performed ERCP in a 97-year-old woman with abdominal pain resulting from acute cholangitis caused by choledocholithiasis and observed difficult biliary cannulation. Eventually, the patient was successfully treated with the rendezvous technique. We could not cannulate the biliary duct during ERCP twice. Therefore, we placed a percutaneous transhepatic gallbladder drainage (PTGBD) tube without intrahepatic dilation. The rendezvous technique was performed using the PTGBD tube. The patient did not experience pancreatitis or perforation.

Short-Term Results of Laparoscopic Radiofrequency Ablation Using a Multipolar System for Localized Hepatocellular Carcinoma.

BACKGROUND AND AIM: Multipolar radiofrequency ablation (RFA) is feasible for the treatment of hepatocellular carcinoma (HCC) for which a large ablative area is planned, and it imposes a light physical burden on patients. Multipolar RFA via the percutaneous approach is performed in the majority of cases, but the efficacy of multipolar RFA with a laparoscopic approach has rarely been studied. This study aimed to evaluate the efficacy and safety of multipolar laparoscopic RFA (LRA) for localized HCC over the short term. METHODS: From January 2014 to January 2016, 77 consecutive patients with 130 HCCs treated by multipolar LRA were assessed. One to three bipolar needle applicators were inserted under laparoscopic ultrasonography guidance, regardless of tumor location. We intended to achieve parallel insertions and no-touch ablation as much as possible. RESULTS: The median size of the main tumor was 22 mm (range, 10-42 mm). The median follow-up time was 13.6 months (range, 3.1-24.8 months). In all cases, a sufficient ablative area was obtained as planned, without thermal injury of adjacent organs. During the follow-up period, all patients were alive with no local tumor progression, while intrahepatic recurrence distant from the primary site occurred in 7 patients. The 2-year local tumor progression-free survival rate and overall cancer-free survival rate were 100 and 81.6%, respectively. There were no procedural major complications caused prolonging the hospitalization, and all patients were discharged without subjective symptoms 4-7 days after LRA. CONCLUSIONS: Multipolar LRA was efficacious in the treatment of localized HCCs by safely achieving a good ablative area.

Asymptomatic anisakiasis of the colon incidentally diagnosed and treated during colonoscopy by retroflexion in the ascending colon.

A 74-year-old man with diabetes underwent colonoscopy as routine screening for colon cancer. An Anisakis larva was found incidentally during colonoscopy using the retroflexion technique in the ascending colon, and was removed using a forceps. Asymptomatic colonic anisakiasis is very rare, and few reports have described diagnosis and treatment of anisakiasis during colonoscopy by the retroflexion technique in the ascending colon. We have reported this rare case along with a literature review.

A case of small hepatocellular carcinoma treated with laparoscopic multipolar radiofrequency ablation with a no-touch ablation procedure.

A 77-year-old man with hepatocellular carcinoma was admitted to our institution. Computed tomography revealed two nodules, one at the surface and one within the liver, ≤3 cm in diameter. We performed laparoscopic radiofrequency ablation using a bipolar system with a "no-touch ablation" procedure using multiple applicators for insertion, not into the tumor directly, but to the perimeter of the tumor. A sufficient ablated area was obtained regardless of tumor location. No operative complications were encountered and adequate therapeutic effect was achieved safely. Laparoscopic multipolar radiofrequency ablation is a feasible procedure for treating hepatocellular carcinoma.

Identification of the transforming activity of Indian hedgehog by retroviral expression screening.

To identify novel cancer-promoting genes in biliary tract cancer (BTC), we constructed a retroviral cDNA expression library from a clinical specimen of BTC with anomalous pancreaticobiliary duct junction (APBDJ), and used the library for a focus formation assay with 3T3 fibroblasts. One of the cDNAs rescued from transformed foci was found to encode Indian hedgehog homolog (IHH). The oncogenic potential of IHH was confirmed both in vitro with the focus formation assay and in vivo with a tumorigenicity assay in nude mice. The isolated IHH cDNA had no sequence alterations, suggesting that upregulation of IHH expression may contribute to malignant transformation. Quantitation of IHH mRNA among clinical specimens has revealed that the expression level of IHH in BTC with APBDJ is higher than that in BTC without APBDJ and than in non-cancerous biliary tissues. Our data thus implicate a direct role of IHH in the carcinogenesis of BTC with APBDJ.

Identification of transforming activity of free fatty acid receptor 2 by retroviral expression screening.

Gallbladder cancer (GBC) is a highly fatal malignancy in humans. Genetic alterations in KRAS or TP53 as well as overexpression of ERBB2 have been shown to contribute to the development of certain types of GBC. However, many cases of GBC do not harbor such genetic changes, with other transforming events awaiting discovery. We here tried to identify novel cancer-promoting genes in GBC, with the use of a retroviral cDNA expression library. A retroviral cDNA expression library was constructed from a surgically resected clinical specimen of GBC, and was used to infect 3T3 fibroblasts in a focus formation assay. cDNA incorporated into the transformed foci was rescued by PCR. One such cDNA was found to encode free fatty acid receptor 2 (FFAR2), a G protein-coupled receptor for short-chain fatty acids. The oncogenic potential of FFAR2 was confirmed both in vitro with the focus formation assay and by evaluation of cell growth in soft agar as well as in vivo with a tumorigenicity assay in nude mice. The isolated FFAR2 cDNA had no sequence alterations, suggesting that upregulation of FFAR2 expression may contribute to malignant transformation. Indeed, all of quantitative RT-PCR, in situ hybridization, and immunohistochemical analyses showed that the amount of FFAR2 mRNA and its protein product was increased in digestive tract cancer specimens. Furthermore, short-chain fatty acids potentiated the mitogenic action of FFAR2 in 3T3 cells. Our data thus, for the first time, implicate FFAR2 in carcinogenesis of the digestive tract.

A case of acute hepatitis C caused by interspousal transmission after 30 years of marriage.

We describe a case of interspousal transmission of hepatitis C virus (HCV) infection after 30 years of marriage which was confirmed by gene analysis. A 60-year-old man was referred to our hospital because of severe hepatic dysfunction. Laboratory findings showed that HCV-Ab titer and qualitative Amplicor HCV were both positive in low levels. Because the patient regularly consumes various health foods, it was initially difficult to rule out drug-induced hepatopathy, but the patient was diagnosed with acute hepatitis C when HCV antibody titer increased 4 months later. Because his wife also tested positive for HCV antibody, interspousal transmission was suspected, and gene analysis was performed. Both husband and wife had HCV 1b, and the base sequence homology of 1087 base pairs (bp) in the NS5B region was 98.6% (99.4% at the amino acid level). In addition, upon analysis of the E1 and E2 junctional region sequence (268 bp) including hypervariable region 1 (HVR-1), a close relationship (89.2-99.6%) between clones obtained from each spouse was observed, thus confirming that the source of infection was his wife. Thorough medical history taking suggested that sexual intercourse was the most likely route of infection. In previous large-scale clinical studies, the frequency of HCV infection between married couples has been extremely low, but it is important to obtain informed consent regarding the potential risk of infection.

Diagnosis of elevated-type early gastric cancers by the optimal band imaging system.

BACKGROUND: The endoscopic diagnosis of an elevated-type early gastric cancer is often difficult. The optimal band imaging (OBI) system can reconstruct the best spectral images decomposed from ordinary endoscopic images with free selection of 3 wavelengths and provide unmagnified images with high light intensity as well as magnified images. OBJECTIVE: To evaluate whether the OBI system facilitates detection of the demarcation lines between an elevated-type early gastric cancer and surrounding tissue and thus is more helpful for performing endoscopic therapy. DESIGN: A prospective study. SETTING: Jichi Medical University, Japan. PATIENTS: Seventy-five patients, 81 lesions with an elevated-type early gastric cancer. MAIN OUTCOME MEASUREMENTS: A comparison between OBI images and conventional endoscopic images in the identification of the demarcation lines of an elevated-type early gastric cancer without magnification and the rate of success in identifying the abnormal surface structure of cancer by using low-magnified OBI images. RESULTS: Demarcation lines were easily identified in OBI images, even without magnification, because such cancers could be clearly distinguished from the surrounding whitish atrophic mucosa. Inexperienced endoscopists could determine demarcation lines with significantly greater accuracy with unmagnified OBI images than with conventional images. With 40-fold magnification, irregular microstructural or nonstructural patterns were also found within cancer lesions in all cases studied but in none of the cases in the surrounding noncancerous mucosa. CONCLUSIONS: The new contrast images obtained with the OBI system enable better determination of the demarcation lines of elevated-type early gastric cancers, and this system may be useful for performing endoscopic therapy of this type of cancer as a new endoscopic modality.