Endoscopy

Introduction
The Endoscopy Division covers three fields of interest: the gastrointestinal (GI) tract, respiratory system and head and neck. A total of 9,526 endoscopic examinations were performed in 2002, of which 8,549 were GI endoscopy, 639 bronchoscopy, and 319 laryngoscopy. Recently, a remarkable increase has been noted in the number of endoscopic treatments, such as endoscopic mucosal resection (EMR), percutaneous endoscopic gastrostomy (PEG), endoscopic dilatation, and metallic stenting. A high detection rate for esophageal carcinoma at GI endoscopy is a characteristic of our hospital, which is explained by the fact that a large number of patients with head and neck cancer who have high risks of synchronous esophageal cancers are examined at our division.
We have operated a digital filing system for endoscopic images since 1997. The filing system allows prompt comparison of new images with older ones of the same patients. The digital images have advantages of high quality resolution and the possibility of long-term preservation using EVIS 240 system. In addition, we have introduced a new operating system for endoscopy called Miracle, which connects with the local area network in the National Cancer Center Hospital East. We have been using the Miracle system for endoscopy since October 2001.

Routine Activities 
An electronic laryngoscope is routinely used in the pretreatment and postoperative evaluations of head and neck cancer patients. We also find it useful in patient education. Recent development of instruments and techniques include metallic stenting for malignant esophageal stenosis, PEG for palliation, ultra-thin cholangio-pancreatoscopy, and adaptive enhancement by image processing. Endoscopic ultrasonography (EUS) provides important information in staging and determining resectability. EUS-guided fine-needle aspiration or biopsy is being conducted in patients with submucosal tumor or nodes adjacent to GI tract wall.
Therapeutic frontiers are also being explored by the use of EMR for early gastrointestinal mucosal cancers. The percentage of cases treated with EMR has been increasing, and this increase is caused by expansion of indications. New techniques, such as endoscopic resection using an insulation-tipped diathermic knife (IT knife) for early gastrointestinal cancer has overcome the limitation in size of tumors treatable with EMR. With regard to colonoscopy, we have used a magnifying endoscope (CF240ZI, Olympus Optical Co., Ltd. Japan) routinely since December 1993. Endoscopic day surgery such as polypectomy and EMR, are now performed in one tenth of all examinations. For diagnosis of early lung cancer, lung biopsy under real-time CT fluoroscopic guidance has been performed in a large number of cases, and has yielded promising results. Brachytherapy is applied to relapsed cases of lung cancer with a high response rate.


New Developments
Correct assessment of gastrointestinal mucosal color is extremely important in the endoscopic diagnosis of digestive tract diseases. New diagnostic method using narrow band imaging system (NBI) has been developed for the examination of the spectral characteristics of tissue in the GI tract and head and neck area. In our study, each lesion in GI tract had its own peculiar spectral characteristics, which suggested that NBI might become a useful modality for clarifying the spectral characteristics of malignant lesions in comparison with benign lesions. It has been clarified that adaptive enhancement by image processing is effective for the diagnosis of crypt pattern of colonic tumors, extent of cancerous invasion in early gastric cancer and ulcer staging . We also can detect the mucosal microvascular pattern and this represents a breakthrough in the detection of very early pharyngeal carcinoma. Image analysis of the fine mucosal network pattern by magnifying endoscopy is also being studied. These studies along with progress in electronic video endoscopy are thought to be the most promising concepts in endoscopic diagnosis. Furthermore, it is very important to develop them for making objective and quantitative diagnosis.
Genetic and immunohistochemical analyses using endoscopic biopsy specimens have allowed the prediction of chemosensitivity and survival in patients with advanced esophageal and gastric cancers. We have also adopted these methods to study the growth and development of hyperplastic polyp (hMLH1 and hMSH2 expression), serrated adenoma, superficial type lesions and synchronous/ metachronous cancers of the colon and rectum. In addition, we have investigated the correlation between bacterial infection and upper GI carcinogenesis. We found that mutant ALDH2-2 allele is strongly associated with multiple dysplastic or cancerous changes in the upper aerodigestive tract and that exhalation of high levels of acetaldehyde and normal oral microflora might be a regional source of this carcinogenic compound upon drinking.

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