食道ヨード不染帯の経過観察

Natural Course of Iodine Unstained Area in the Esophagus in Massscreening Programs

要旨　集検施設において健康成人を対象として，食道癌high risk group を設定し，食道ヨード染色併用内視鏡検診による，食道ヨード不染帯と早期食道癌のスクリーニングを行った．内視鏡検査31,776例中1,512例にヨード染色が施行され，ヨード染色例中546例（36.1％）にヨード不染帯が発見され，14例（0.93％）の食道癌，35例（2.31％）の異型上皮が発見された．癌・異型上皮によるヨード不染帯は径5mm以上の明瞭な不染帯となることが多く，不染帯の色調が鑑別の重要な点と考えられた．不染帯の経過観察では異型上皮と診断されたヨード不染帯35例中8例に経過観察中に食道癌が確認され，これらの例ではその変化の時間的経過は緩やかであり，確実な内視鏡経過観察を行うことが重要であると考えられた．変化を来す可能性の高い不染帯の形態，対策についても検討した．

　A total of 546 cases of iodine unstained areas in the esophagus were detected by iodine staining during esophagoscopic examination in mass screening programs over the past 10 years at Keio Cancer Detection Center. Among the 546 areas unstained by iodine, we diagnosed 14 cases of esophageal carcinoma and 35 cases of dysplasia. The frequency of areas unstained by iodine was about 36.1% in Keio CDC, and the frequency of carcinoma was about 0.93% and the frequency of dysplasia was about 2.31%. There are some characteristics of the areas unstained by iodine due the carcinoma and dysplasia. Most iodine-unstained area is lager than 5mm in diameter, and it is clearly margined and white in color. The most important characteristic of iodine unstained area to distinguish maligant lesions is the color.

　We observed and followed these 35 dysplasia cases extensively and discovered that eight cases of dysplasias increaed in diameter during the period of observation and developed into intraepithelial cancer. These eight cases were resected by surgery either via thracotomy or via the esophagofiberscope. All these cases were early cancers. As the speed of cancer growth is slow in most cases, the important point for detection of carcinoma is strict and extensive follow-up by endoscopy.