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doi:10.1111/jgh.12797
O R I G I N A L A RT I C L E
Evaluation of gastric cancer diagnosis using new ultrathin transnasal endoscopy with narrow-band imaging: Preliminary study Takashi Kawai,* Kyosuke Yanagizawa,* Sakiko Naito,* Hiroko Sugimoto,* Masakatsu Fukuzawa,† Takuji Gotoda,† Jun Matsubayashi,‡ Toshitaka Nagao,‡ Sumito Hoshino,§ Akihiko Tsuchida§ and Fuminori Moriyasu† *Endoscopy Centre, §3rd Department of Surgery, Tokyo Medical University Hospital, †Department of Gastroenterology and Hepatology, and ‡ Department of Anatomic Pathology, Tokyo Medical University Hospital, Tokyo, Japan
Key words transnasal endoscopy, gastric cancer, Narrow band imaging, close examination, mucosal structure. Correspondence Dr Takashi Kawai, Endoscopy Center, Tokyo Medical University Hospital, 6-7-1, Nishi-Shinjuku, Shinjuku-ku, Tokyo 160-0023, Japan. Email: [email protected]
Abstract Background and Aim: The new developed ultrathin transnasal endoscope, the GIF-XP290N, makes possible a resolving power similar to the GIF-H260 at a distance of 3 mm. In this study, using the GIF-XP290N, we evaluated whether endoscopic diagnosis (discrimination between benign and malignant) of gastric lesions is possible using nonmagnified narrow-band imaging (NBI) endoscopy. Methods: The subjects were 255 consecutive patients who underwent screening of the gastrointestinal tract using new ultrathin transnasal endoscopy. Their average age was 65.2 ± 11.4 years. The male-female ratio was 2.5:1. All cases were examined using conventional white-light imaging (WLI) and nonmagnified NBI. When a depressed lesion was detected in the stomach, it was examined using WLI, then NBI close examination (at about 3 mm). We observed the mucosal structure of the lesion using close visualization with NBI. Concerning mucosal structural changes, we looked for a clear demarcation line between the lesion and the surrounding mucosa, and loss, irregularity, or nonuniformity of the lesion mucosal microsurface pattern. Results: A total of 52 depressed lesions were examined. The histological diagnosis was cancer for 8 lesions, and noncancer for 44 lesions. WLI examination yielded a sensitivity of 50.0% (4/8), specificity of 63.6% (28/44), and accuracy 61.5% (32/52). On the other hand, NBI close examination yielded a sensitivity of 87.5% (7/8), specificity of 93.2% (41/44), and accuracy of 92.3% (48/52), significantly higher. Conclusion: NBI close examination using ultrathin transnasal endoscopy enables mucosal diagnosis even without magnification and was considered to be an effective technique for improving endoscopic diagnosis.
Introduction In screening of the upper digestive tract in recent years, ultrathin transnasal endoscopy has been widely used because there is little discomfort and minimal effect on circulatory dynamics.1 However, because the endoscope is ultrathin, in comparison with transoral endoscopy, the image is inferior, particularly in terms of the optical resolution. Toyoizumi et al. reported that for ultrathin endoscopy, the detection rate for early gastric cancer is significantly lower than with high vision transoral endoscopy.2 The recently developed new ultrathin transnasal endoscope, the GIF-XP290N (Olympus Medical System, Tokyo, Japan), has a brighter light source and uses an objective optical system that prevents any reduction in contrast when the endoscope tip nears the area of interest. This makes possible a resolving power similar to the
GIF-H260 at a distance of 3 mm, and it has been reported that close examination using narrow-band imaging (NBI) enables us to delineate the mucosal structure.3 In this study, using the GIFXP290N, we evaluated whether qualitative diagnosis (discrimination between benign and malignant) of gastric lesions is possible using nonmagnified NBI endoscopy, and evaluated whether it is possible to improve endoscopic diagnostic ability and avoid unnecessary biopsies.
Methods This study was conducted at the Tokyo Medical University Hospital Endoscopy Center between August 2012 and December 2013. The subjects were 255 consecutive patients who underwent
Journal of Gastroenterology and Hepatology 2014; 29 (Suppl. 4): 33–36 © 2014 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd
33
New transnasal endoscopy and gastric cancer
Table 1
T Kawai et al.
Characteristics of subjects
Atrophic Gastritis Gastric polyp Gastric ulcer Duodenal ulcer GERD Esophageal cancer Gastric cancer MALToma
139 50 16 11 19 6 12 2
GERD, Gastro-esophageal reflux; MALToma, Mucosa Associated Lymphoid Tissue lymphoma.
Histological examination. After fixing the biopsy specimens in formalin, they were embedded in paraffin, and 4-μm slices were made. Histological examinations were conducted in accordance with the revised Vienna classification. Lesions diagnosed as Category 4 were diagnosed as gastric cancer. Statistical analysis. Statistical analyses were performed using analysis software SPSS®16.0J for Windows (SPSSR22.0J, IBM, New York, USA). For diagnostic performance, accuracy, sensitivity, and specificity are presented as percentages with 95% confidence interval (CI). P < 0.05 was considered significant.
Results screening of the gastrointestinal tract using new ultrathin transnasal endoscopy. Their average age was 65.2 ± 11.4 years. The male-female ratio was 2.4:1. All cases were examined using conventional white-light imaging (WLI) and nonmagnified NBI. Subject characteristics are shown in Table 1.
Participating endoscopists. All examination was performed by five endoscopic specialists (T.K., K.Y., S.N., H.S., M.F.). These endoscopists were accredited by the Japan Gastroenterologiacal Endoscopy Society.
A total of 52 depressed lesions were examined. The histological diagnosis was cancer for 8 lesions, and noncancer for 44 lesions. WLI examination yielded a sensitivity of 50.0% (4/8, 95% CI: 15.7–84.3), specificity of 63.6% (28/44, 95% CI: 47.7–77.6), and accuracy 61.5% (32/52, 95% CI: 47.0–74.7). On the other hand, NBI close examination yielded a sensitivity of 87.5% (7/8, 95% CI: 47.3–99.7), specificity of 93.2% (41/44, 95% CI: 81.3–98.6), and accuracy 92.3% (48/52, 95% CI: 81.5–97.8), significantly higher.
Discussion Diagnostic criteria for WLI AND NBI. When a depressed lesion was detected in the stomach, it was examined using WLI, then NBI close examination (at about 3 mm). Using WLI, we examined the lesion size and color characteristics, characteristics of the lesion surface, surrounding mucosa, and gastric rugae. Lesions were classified as malignant, suspected malignant, or benign. On the other hand, for close visualization using NBI, we observed the mucosal structure of the lesion. Concerning mucosal structural changes, we looked for a clear demarcation line between the lesion and the surrounding mucosa, and loss, irregularity, or nonuniformity of the lesion mucosal microsurface pattern (Figs 1–3) in accordance with the magnifying endoscopy with NBI categories of Yao et al.4 and Kaise et al.5; if both findings are present, the diagnosis is malignant. If either or both findings were absent, the diagnosis was benign. Biopsies were taken from all lesions for histological examination. Patients 20 years old or younger, and those with a history of gastrointestinal surgery, including the esophagus and stomach, were excluded from this study. The study protocol conformed to the 1975 Helsinki Declaration concerning human experiments, as revised in 1983. Informed consent was obtained from all subjects.
Transnasal endoscopy. Endoscopic examinations were conducted without sedation. We used the Olympus GIF-XP290N new transnasal endoscope (outer diameter at the distal end 5.0 mm, Olympus Medical System), and an electric endoscopic system (Evis Lucera Elite, Olympus Medical System). Premedication and anesthesia to the nasal cavity were performed as previously described.1 Anticonvulsants such as scopolamine butylbromide were not administered as premedication. 34
Endoscopic diagnoses are influenced by endoscope factors and endoscopist factors. Endoscope factors include image quality (resolution, brightness, contrast, water dispersion, etc.), scope ease of operation (field of view, ease of passage, etc.), biopsy operability (precision of aim, angle operation, etc.); whereas endoscopist factors include years of experience and knowledge of the endoscope. In particular, Yoshida et al. reported that for ultrathin transnasal endoscopy, the years of experience strongly influences diagnostic ability.6 In recent years, various image enhancement methods have been introduced to improve endoscopic detection rates. For the diagnosis of early gastric cancer, Ezoe et al. reported that magnifying endoscopy with NBI significantly improves the ability to detect demarcation lines and vascular structural abnormalities compared with conventional WLI.7 Kato et al.8 and Kaise et al.5 similarly reported the effectiveness of magnifying endoscopy with NBI in the detection of gastric cancer. Furthermore, Li et al. using confocal laser microscopy9 and Inoue et al. using endocytoscopy10 reported that they have been able to endoscopically visualize images close to the histopathological findings, and this is useful in the detection of gastric cancer. However, these magnifying endoscopes are larger in caliber, often requiring sedation. Furthermore, cumbersome premedication of dyes or fluorescent substances, intravenously or intralumenally, may be necessary. Accordingly, in this trial, we evaluated whether it was possible to use ultrathin transnasal endoscopy, widely used in screening tests, to differentiate between benign and malignant lesions through visualization of the mucosal structure using nonmagnified close examination with NBI. We found that for mucosal structure diagnosis using NBI nonmagnified close examination, the sensitivity was 80% and the specificity 88.3%, clearly superior to WLI. One reason why NBI examination improves visualization of neoplastic
Journal of Gastroenterology and Hepatology 2014; 29 (Suppl. 4): 33–36 © 2014 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd
T Kawai et al.
New transnasal endoscopy and gastric cancer
Figure 1 White-light finding, narrow-band imaging (NBI) and schema relating to depressive mucosal pattern (noncancerous lesion: Vienna classification: C1). Left side: (white-light image) clear and irregular margin, spiny depression. Middle side: (NBI close examination) demarcation line (+), abnormality of mucosal pattern (−). Right side: schema of the NBI pattern.
Figure 2 White-light finding, narrow-band imaging (NBI) and schema relating to depressive mucosal pattern (cancerous lesion: Vienna classification: C4). Left side: (white-light image) discoloration, clear and irregular margin, spiny depression. Middle side: (NBI close examination) demarcation line (+), loss of mucosal pattern (+). Right side: schema of the NBI pattern.
lesions compared with white-light examination is that the mucosal structural pattern is bordered by whitish lines, and these whitish lines have an important meaning. For example, in a benign lesion that resembles cancer, even if glands are associated with intestinal metaplasia and inflammation, at a fixed distance, the cells are aligned at a tangent to the NBI afferent light, so whitish lines are clearly visible and the mucosal pattern is retained. On the other hand, if for example the cancer glands are differentiated gastric cancer, distortion of the duct structure means few cells are aligned at a tangent to the NBI incoming rays, resulting in insufficient scattering of light to delineate the whitish lines, so the mucosal structural pattern is lost or unclear. Naturally, unlike a magnifying endoscopic examination, the vascular structure cannot be discerned, but it is of great significance that diagnostic ability is improved by observing the mucosal structure alone. With WLI until now, diagnosis is based on the size and color of the lesion, and the characteristics of the lesion surface, surround-
ing mucosa, and gastric rugae, making the experience of the endoscopist important and causing great variability in the findings. Furthermore, the diagnostic process involved the following histological and qualitative process: (i) close examination of the entire stomach; (ii) recognition (detection) of the presence of a lesion; and (iii) taking a biopsy of the lesion. A similar diagnostic process occurs with transnasal endoscopy. However, histological examination of the biopsy specimen often produces a benign diagnosis, so many biopsies are actually unnecessary. In recent years, the efficacy of secondary preventative antiplatelet therapy, in particular low-dose aspirin, has been confirmed for a wide range of arteriosclerotic diseases, from myocardial infarction to stroke, by meta-analyses such as that conducted by the Antithrombotic Trialists’ Collaboration,11 and prescriptions for antiplatelet agents have increased rapidly. The proportion of patients undergoing endoscopic examinations on antiplatelet therapy has also risen. Until recently, it was routine to suspend antiplatelet therapy for some time prior to an endoscopy, but it has
Journal of Gastroenterology and Hepatology 2014; 29 (Suppl. 4): 33–36 © 2014 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd
35
New transnasal endoscopy and gastric cancer
T Kawai et al.
Figure 3 White-light finding, narrow-band imaging (NBI) and schema relating to depressive mucosal pattern (cancerous lesion: Vienna classification: C4). Left side: (white-light image) irregularity of mucosa, clear and irregular margin, spiny depression. Middle side: (NBI close examination) demarcation line (+), irregularity of mucosal pattern (+). Right side: schema of the NBI pattern.
been reported that the risk of a cardiac event increases 3.14 times when patients with coronary artery disease discontinue aspirin therapy.12 In July 2012, the Japan Gastroenterological Endoscopy Society13 published new guidelines regarding antiplatelet therapy, and it is now possible to perform biopsies without ceasing aspirin. However, there is a possibility of bleeding after the biopsy, so this is limited to cases where malignancy is strongly suspected. Accordingly, the use of nonmagnified close examination with NBI in screening endoscopies, as conducted in this study, is expected to become more important in the future. We anticipate that the diagnostic capability of ultrathin transnasal endoscopy in screening endoscopies will continue to improve in the future.
References 1 Kawai T, Miyazaki I, Yagi K et al. Comparison of the effects on cardiopulmonary function of ultrathin transnasal versus normal diameter transoral esophagogastroduodenoscopy in Japan. Hepatogastroenterology 2007; 54: 770–4. 2 Toyoizumi H, Kaise M, Arakawa H et al. Ultrathin endoscopy versus high-resolution endoscopy for diagnosing superficial gastric neoplasia. Gastrointest. Endosc. 2009; 70: 240–5. 3 Kawai T, Fukuzawa M, Gotoda T. Evolution of ultra thin endoscope. Dig. Endosc. 2013; 25: 46. 4 Yao K, Iwashita A, Tanabe H et al. Novel zoom endoscopy technique for diagnosis of small flat gastric cancer: a prospective, blind study. Clin. Gastroenterol. Hepatol. 2007; 5: 869–78. 5 Kaise M, Kato M, Urashima M et al. Magnifying endoscopy combined with narrow-band imaging for differential diagnosis of superficial depressed gastric lesions. Endoscopy 2009; 41: 310–5.
36
6 Yoshida Y, Hayami Y, Matuoka M, Nakayama S. Comparison of endoscopic detection rate of early gastric cancer and gastric adenoma using transnasal EGD with that of transoral EGD. Dig. Endosc. 2008; 20: 184–9. 7 Ezoe Y, Muto M, Uedo N et al. Magnifying narrowband imaging is more accurate than conventional white-light imaging in diagnosis of gastric mucosal cancer. Gastroenterology 2011; 141: 2017–25. doi: 10.1053/j.gastro.2011.08.007. 8 Kato M, Kaise M, Yonezawa J et al. Magnifying endoscopy with narrow-band imaging achieves superior accuracy in the differential diagnosis of superficial gastric lesions identified with white-light endoscopy: a prospective study. Gastrointest. Endosc. 2010; 72: 523–9. doi: 10.1016/j.gie.2010.04.041. 9 Li Z, Zuo XL, Li CQ et al. In vivo molecular imaging of gastric cancer by targeting MG7 antigen with confocal laser endomicroscopy. Endoscopy 2013; 45: 79–85. doi: 10.1055/s-0032-1325762. 10 Inoue H, Sasajima K, Kaga M et al. Endoscopic in vivo evaluation of tissue atypia in the esophagus using a newly designed integrated endocytoscope: a pilot trial. Endoscopy 2006; 38: 891–5. 11 Antithrombotic Trialists’ Collaboration. Collaborative meta-analysis of randomized trials of antiplatelet therapy for prevention of death, myocardial infarction, and stroke in high risk patients. BMJ 2002; 324: 71–86. 12 Biondi-Zoccai GG, Lotrionte M, Agostoni P et al. A systematic review and meta-analysis on the hazards of discontinuing or not adhering to aspirin among 50 279 patients at risk for coronary artery disease. Eur. Heart J. 2006; 27: 2667–74. 13 Fujimoto K, Fujishiro M, Kato M et al.; Japan Gastroenterological Endoscopy Society. Guidelines for gastroenterological endoscopy in patients undergoing antithrombotic treatment. Dig. Endosc. 2014; 26: 1–14. doi: 10.1111/den.12183.
Journal of Gastroenterology and Hepatology 2014; 29 (Suppl. 4): 33–36 © 2014 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd
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doi:10.1111/jgh.12797
O R I G I N A L A RT I C L E
Evaluation of gastric cancer diagnosis using new ultrathin transnasal endoscopy with narrow-band imaging: Preliminary study Takashi Kawai,* Kyosuke Yanagizawa,* Sakiko Naito,* Hiroko Sugimoto,* Masakatsu Fukuzawa,† Takuji Gotoda,† Jun Matsubayashi,‡ Toshitaka Nagao,‡ Sumito Hoshino,§ Akihiko Tsuchida§ and Fuminori Moriyasu† *Endoscopy Centre, §3rd Department of Surgery, Tokyo Medical University Hospital, †Department of Gastroenterology and Hepatology, and ‡ Department of Anatomic Pathology, Tokyo Medical University Hospital, Tokyo, Japan
Key words transnasal endoscopy, gastric cancer, Narrow band imaging, close examination, mucosal structure. Correspondence Dr Takashi Kawai, Endoscopy Center, Tokyo Medical University Hospital, 6-7-1, Nishi-Shinjuku, Shinjuku-ku, Tokyo 160-0023, Japan. Email: [email protected]
Abstract Background and Aim: The new developed ultrathin transnasal endoscope, the GIF-XP290N, makes possible a resolving power similar to the GIF-H260 at a distance of 3 mm. In this study, using the GIF-XP290N, we evaluated whether endoscopic diagnosis (discrimination between benign and malignant) of gastric lesions is possible using nonmagnified narrow-band imaging (NBI) endoscopy. Methods: The subjects were 255 consecutive patients who underwent screening of the gastrointestinal tract using new ultrathin transnasal endoscopy. Their average age was 65.2 ± 11.4 years. The male-female ratio was 2.5:1. All cases were examined using conventional white-light imaging (WLI) and nonmagnified NBI. When a depressed lesion was detected in the stomach, it was examined using WLI, then NBI close examination (at about 3 mm). We observed the mucosal structure of the lesion using close visualization with NBI. Concerning mucosal structural changes, we looked for a clear demarcation line between the lesion and the surrounding mucosa, and loss, irregularity, or nonuniformity of the lesion mucosal microsurface pattern. Results: A total of 52 depressed lesions were examined. The histological diagnosis was cancer for 8 lesions, and noncancer for 44 lesions. WLI examination yielded a sensitivity of 50.0% (4/8), specificity of 63.6% (28/44), and accuracy 61.5% (32/52). On the other hand, NBI close examination yielded a sensitivity of 87.5% (7/8), specificity of 93.2% (41/44), and accuracy of 92.3% (48/52), significantly higher. Conclusion: NBI close examination using ultrathin transnasal endoscopy enables mucosal diagnosis even without magnification and was considered to be an effective technique for improving endoscopic diagnosis.
Introduction In screening of the upper digestive tract in recent years, ultrathin transnasal endoscopy has been widely used because there is little discomfort and minimal effect on circulatory dynamics.1 However, because the endoscope is ultrathin, in comparison with transoral endoscopy, the image is inferior, particularly in terms of the optical resolution. Toyoizumi et al. reported that for ultrathin endoscopy, the detection rate for early gastric cancer is significantly lower than with high vision transoral endoscopy.2 The recently developed new ultrathin transnasal endoscope, the GIF-XP290N (Olympus Medical System, Tokyo, Japan), has a brighter light source and uses an objective optical system that prevents any reduction in contrast when the endoscope tip nears the area of interest. This makes possible a resolving power similar to the
GIF-H260 at a distance of 3 mm, and it has been reported that close examination using narrow-band imaging (NBI) enables us to delineate the mucosal structure.3 In this study, using the GIFXP290N, we evaluated whether qualitative diagnosis (discrimination between benign and malignant) of gastric lesions is possible using nonmagnified NBI endoscopy, and evaluated whether it is possible to improve endoscopic diagnostic ability and avoid unnecessary biopsies.
Methods This study was conducted at the Tokyo Medical University Hospital Endoscopy Center between August 2012 and December 2013. The subjects were 255 consecutive patients who underwent
Journal of Gastroenterology and Hepatology 2014; 29 (Suppl. 4): 33–36 © 2014 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd
33
New transnasal endoscopy and gastric cancer
Table 1
T Kawai et al.
Characteristics of subjects
Atrophic Gastritis Gastric polyp Gastric ulcer Duodenal ulcer GERD Esophageal cancer Gastric cancer MALToma
139 50 16 11 19 6 12 2
GERD, Gastro-esophageal reflux; MALToma, Mucosa Associated Lymphoid Tissue lymphoma.
Histological examination. After fixing the biopsy specimens in formalin, they were embedded in paraffin, and 4-μm slices were made. Histological examinations were conducted in accordance with the revised Vienna classification. Lesions diagnosed as Category 4 were diagnosed as gastric cancer. Statistical analysis. Statistical analyses were performed using analysis software SPSS®16.0J for Windows (SPSSR22.0J, IBM, New York, USA). For diagnostic performance, accuracy, sensitivity, and specificity are presented as percentages with 95% confidence interval (CI). P < 0.05 was considered significant.
Results screening of the gastrointestinal tract using new ultrathin transnasal endoscopy. Their average age was 65.2 ± 11.4 years. The male-female ratio was 2.4:1. All cases were examined using conventional white-light imaging (WLI) and nonmagnified NBI. Subject characteristics are shown in Table 1.
Participating endoscopists. All examination was performed by five endoscopic specialists (T.K., K.Y., S.N., H.S., M.F.). These endoscopists were accredited by the Japan Gastroenterologiacal Endoscopy Society.
A total of 52 depressed lesions were examined. The histological diagnosis was cancer for 8 lesions, and noncancer for 44 lesions. WLI examination yielded a sensitivity of 50.0% (4/8, 95% CI: 15.7–84.3), specificity of 63.6% (28/44, 95% CI: 47.7–77.6), and accuracy 61.5% (32/52, 95% CI: 47.0–74.7). On the other hand, NBI close examination yielded a sensitivity of 87.5% (7/8, 95% CI: 47.3–99.7), specificity of 93.2% (41/44, 95% CI: 81.3–98.6), and accuracy 92.3% (48/52, 95% CI: 81.5–97.8), significantly higher.
Discussion Diagnostic criteria for WLI AND NBI. When a depressed lesion was detected in the stomach, it was examined using WLI, then NBI close examination (at about 3 mm). Using WLI, we examined the lesion size and color characteristics, characteristics of the lesion surface, surrounding mucosa, and gastric rugae. Lesions were classified as malignant, suspected malignant, or benign. On the other hand, for close visualization using NBI, we observed the mucosal structure of the lesion. Concerning mucosal structural changes, we looked for a clear demarcation line between the lesion and the surrounding mucosa, and loss, irregularity, or nonuniformity of the lesion mucosal microsurface pattern (Figs 1–3) in accordance with the magnifying endoscopy with NBI categories of Yao et al.4 and Kaise et al.5; if both findings are present, the diagnosis is malignant. If either or both findings were absent, the diagnosis was benign. Biopsies were taken from all lesions for histological examination. Patients 20 years old or younger, and those with a history of gastrointestinal surgery, including the esophagus and stomach, were excluded from this study. The study protocol conformed to the 1975 Helsinki Declaration concerning human experiments, as revised in 1983. Informed consent was obtained from all subjects.
Transnasal endoscopy. Endoscopic examinations were conducted without sedation. We used the Olympus GIF-XP290N new transnasal endoscope (outer diameter at the distal end 5.0 mm, Olympus Medical System), and an electric endoscopic system (Evis Lucera Elite, Olympus Medical System). Premedication and anesthesia to the nasal cavity were performed as previously described.1 Anticonvulsants such as scopolamine butylbromide were not administered as premedication. 34
Endoscopic diagnoses are influenced by endoscope factors and endoscopist factors. Endoscope factors include image quality (resolution, brightness, contrast, water dispersion, etc.), scope ease of operation (field of view, ease of passage, etc.), biopsy operability (precision of aim, angle operation, etc.); whereas endoscopist factors include years of experience and knowledge of the endoscope. In particular, Yoshida et al. reported that for ultrathin transnasal endoscopy, the years of experience strongly influences diagnostic ability.6 In recent years, various image enhancement methods have been introduced to improve endoscopic detection rates. For the diagnosis of early gastric cancer, Ezoe et al. reported that magnifying endoscopy with NBI significantly improves the ability to detect demarcation lines and vascular structural abnormalities compared with conventional WLI.7 Kato et al.8 and Kaise et al.5 similarly reported the effectiveness of magnifying endoscopy with NBI in the detection of gastric cancer. Furthermore, Li et al. using confocal laser microscopy9 and Inoue et al. using endocytoscopy10 reported that they have been able to endoscopically visualize images close to the histopathological findings, and this is useful in the detection of gastric cancer. However, these magnifying endoscopes are larger in caliber, often requiring sedation. Furthermore, cumbersome premedication of dyes or fluorescent substances, intravenously or intralumenally, may be necessary. Accordingly, in this trial, we evaluated whether it was possible to use ultrathin transnasal endoscopy, widely used in screening tests, to differentiate between benign and malignant lesions through visualization of the mucosal structure using nonmagnified close examination with NBI. We found that for mucosal structure diagnosis using NBI nonmagnified close examination, the sensitivity was 80% and the specificity 88.3%, clearly superior to WLI. One reason why NBI examination improves visualization of neoplastic
Journal of Gastroenterology and Hepatology 2014; 29 (Suppl. 4): 33–36 © 2014 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd
T Kawai et al.
New transnasal endoscopy and gastric cancer
Figure 1 White-light finding, narrow-band imaging (NBI) and schema relating to depressive mucosal pattern (noncancerous lesion: Vienna classification: C1). Left side: (white-light image) clear and irregular margin, spiny depression. Middle side: (NBI close examination) demarcation line (+), abnormality of mucosal pattern (−). Right side: schema of the NBI pattern.
Figure 2 White-light finding, narrow-band imaging (NBI) and schema relating to depressive mucosal pattern (cancerous lesion: Vienna classification: C4). Left side: (white-light image) discoloration, clear and irregular margin, spiny depression. Middle side: (NBI close examination) demarcation line (+), loss of mucosal pattern (+). Right side: schema of the NBI pattern.
lesions compared with white-light examination is that the mucosal structural pattern is bordered by whitish lines, and these whitish lines have an important meaning. For example, in a benign lesion that resembles cancer, even if glands are associated with intestinal metaplasia and inflammation, at a fixed distance, the cells are aligned at a tangent to the NBI afferent light, so whitish lines are clearly visible and the mucosal pattern is retained. On the other hand, if for example the cancer glands are differentiated gastric cancer, distortion of the duct structure means few cells are aligned at a tangent to the NBI incoming rays, resulting in insufficient scattering of light to delineate the whitish lines, so the mucosal structural pattern is lost or unclear. Naturally, unlike a magnifying endoscopic examination, the vascular structure cannot be discerned, but it is of great significance that diagnostic ability is improved by observing the mucosal structure alone. With WLI until now, diagnosis is based on the size and color of the lesion, and the characteristics of the lesion surface, surround-
ing mucosa, and gastric rugae, making the experience of the endoscopist important and causing great variability in the findings. Furthermore, the diagnostic process involved the following histological and qualitative process: (i) close examination of the entire stomach; (ii) recognition (detection) of the presence of a lesion; and (iii) taking a biopsy of the lesion. A similar diagnostic process occurs with transnasal endoscopy. However, histological examination of the biopsy specimen often produces a benign diagnosis, so many biopsies are actually unnecessary. In recent years, the efficacy of secondary preventative antiplatelet therapy, in particular low-dose aspirin, has been confirmed for a wide range of arteriosclerotic diseases, from myocardial infarction to stroke, by meta-analyses such as that conducted by the Antithrombotic Trialists’ Collaboration,11 and prescriptions for antiplatelet agents have increased rapidly. The proportion of patients undergoing endoscopic examinations on antiplatelet therapy has also risen. Until recently, it was routine to suspend antiplatelet therapy for some time prior to an endoscopy, but it has
Journal of Gastroenterology and Hepatology 2014; 29 (Suppl. 4): 33–36 © 2014 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd
35
New transnasal endoscopy and gastric cancer
T Kawai et al.
Figure 3 White-light finding, narrow-band imaging (NBI) and schema relating to depressive mucosal pattern (cancerous lesion: Vienna classification: C4). Left side: (white-light image) irregularity of mucosa, clear and irregular margin, spiny depression. Middle side: (NBI close examination) demarcation line (+), irregularity of mucosal pattern (+). Right side: schema of the NBI pattern.
been reported that the risk of a cardiac event increases 3.14 times when patients with coronary artery disease discontinue aspirin therapy.12 In July 2012, the Japan Gastroenterological Endoscopy Society13 published new guidelines regarding antiplatelet therapy, and it is now possible to perform biopsies without ceasing aspirin. However, there is a possibility of bleeding after the biopsy, so this is limited to cases where malignancy is strongly suspected. Accordingly, the use of nonmagnified close examination with NBI in screening endoscopies, as conducted in this study, is expected to become more important in the future. We anticipate that the diagnostic capability of ultrathin transnasal endoscopy in screening endoscopies will continue to improve in the future.
References 1 Kawai T, Miyazaki I, Yagi K et al. Comparison of the effects on cardiopulmonary function of ultrathin transnasal versus normal diameter transoral esophagogastroduodenoscopy in Japan. Hepatogastroenterology 2007; 54: 770–4. 2 Toyoizumi H, Kaise M, Arakawa H et al. Ultrathin endoscopy versus high-resolution endoscopy for diagnosing superficial gastric neoplasia. Gastrointest. Endosc. 2009; 70: 240–5. 3 Kawai T, Fukuzawa M, Gotoda T. Evolution of ultra thin endoscope. Dig. Endosc. 2013; 25: 46. 4 Yao K, Iwashita A, Tanabe H et al. Novel zoom endoscopy technique for diagnosis of small flat gastric cancer: a prospective, blind study. Clin. Gastroenterol. Hepatol. 2007; 5: 869–78. 5 Kaise M, Kato M, Urashima M et al. Magnifying endoscopy combined with narrow-band imaging for differential diagnosis of superficial depressed gastric lesions. Endoscopy 2009; 41: 310–5.
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6 Yoshida Y, Hayami Y, Matuoka M, Nakayama S. Comparison of endoscopic detection rate of early gastric cancer and gastric adenoma using transnasal EGD with that of transoral EGD. Dig. Endosc. 2008; 20: 184–9. 7 Ezoe Y, Muto M, Uedo N et al. Magnifying narrowband imaging is more accurate than conventional white-light imaging in diagnosis of gastric mucosal cancer. Gastroenterology 2011; 141: 2017–25. doi: 10.1053/j.gastro.2011.08.007. 8 Kato M, Kaise M, Yonezawa J et al. Magnifying endoscopy with narrow-band imaging achieves superior accuracy in the differential diagnosis of superficial gastric lesions identified with white-light endoscopy: a prospective study. Gastrointest. Endosc. 2010; 72: 523–9. doi: 10.1016/j.gie.2010.04.041. 9 Li Z, Zuo XL, Li CQ et al. In vivo molecular imaging of gastric cancer by targeting MG7 antigen with confocal laser endomicroscopy. Endoscopy 2013; 45: 79–85. doi: 10.1055/s-0032-1325762. 10 Inoue H, Sasajima K, Kaga M et al. Endoscopic in vivo evaluation of tissue atypia in the esophagus using a newly designed integrated endocytoscope: a pilot trial. Endoscopy 2006; 38: 891–5. 11 Antithrombotic Trialists’ Collaboration. Collaborative meta-analysis of randomized trials of antiplatelet therapy for prevention of death, myocardial infarction, and stroke in high risk patients. BMJ 2002; 324: 71–86. 12 Biondi-Zoccai GG, Lotrionte M, Agostoni P et al. A systematic review and meta-analysis on the hazards of discontinuing or not adhering to aspirin among 50 279 patients at risk for coronary artery disease. Eur. Heart J. 2006; 27: 2667–74. 13 Fujimoto K, Fujishiro M, Kato M et al.; Japan Gastroenterological Endoscopy Society. Guidelines for gastroenterological endoscopy in patients undergoing antithrombotic treatment. Dig. Endosc. 2014; 26: 1–14. doi: 10.1111/den.12183.
Journal of Gastroenterology and Hepatology 2014; 29 (Suppl. 4): 33–36 © 2014 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd
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