表在性の中・下咽頭癌の拡大内視鏡診断―NBIも含めて

Endoscopic Diagnosis for Superficial Cancers in the Oropharynx and Hypopharynx: Magnifying and Narrow Band Imaging

要旨　これまで中・下咽頭癌の多くは自覚症状を伴って進行癌で発見されることがほとんどであった．また，中・下咽頭癌と食道癌の重複は，半世紀以上もfield cancerization現象なる概念で理解されてきたが，中・下咽頭癌の早期発見につながることはなかった．最近，そのメカニズムの一部が解明され，中・下咽頭癌の高危険群の一部が明らかにされた．さらに新しい内視鏡技術：narrow band imaging（NBI）の応用によって，これまで困難であった早期発見が容易に可能になった．すなわち，高危険群の絞り込みから，効果的な早期診断を一貫して行うことが実際の臨床の現場でも必要とされつつある．今後，NBI機能を併用した拡大観察が一般化されることによって，中・下咽頭の表在癌が発見されやすくなり，声を失ったり，嚥下障害で苦しむ患者さんが少しでも減少することが望まれる．本稿では，NBI機能を含めた拡大観察で，表在性の中・下咽頭癌がどのように観察されるかを解説し，将来の内視鏡診断の参考になることを期待したい．

　Almost all of the patients with cancer in the oropharynx and hypopharynx have been diagnosed at the advanced stage with symptoms such as dysphagia. In addition, although multiple development of cancers in the esophagus, head and neck region have been well-known as the “field cancerization” phenomenon for five decades, there are no modalities for effective screening for early cancers in the oropharynx and hypopharynx. Recent studies have revealed the mechanism of this phenomenon, and groundbreaking technology in endoscopic, narrow band imaging (NBI), allows us to detect them easily. Effective early screening using magnifying endoscopy coupled with NBI might make it possible to reduce the suffering of patients due to loss of the functions of speaking and swallowing after radical surgery. We described the magnifying endoscopic findings of superficial lesions in the oropharynx and hypopharynx together with NBI findings, and we hope that these findings may help to establish future strategies for diagnosis in this field.