咽頭癌治療後の異時性多発癌，遺残再発病変に対する診療の実際

Diagnosis and Treatment of Metachronous Multiple Cancer and Residual Cancer after Treatment for Pharyngeal Cancer

要旨●咽頭癌に対する内視鏡的切除後には，温存された咽喉頭からしばしば異時性多発癌が発症するが，食道癌と同様に，背景粘膜に多発ヨード不染帯が認められる症例で発症率が高いため，治療時における咽頭ヨード染色像の評価は経過観察ストラテジーの判断に重要である．咽頭癌放射線治療後の内視鏡サーベイランスは，粘膜障害を加味した評価が必要であり，検査中の喉頭浮腫にも気を付ける必要がある．照射後異時性多発癌も内視鏡的切除の適応となるが，粘膜治癒は遷延し，感染も来しやすくなる．照射後の遺残再発咽頭癌に対するサルベージ治療としても内視鏡的切除は選択肢の一つとなる．同治療法は技術的には困難でリスクはあるが，喉頭が温存できる恩恵は大きい．

　Metachronous multiple cancer often develops in the preserved laryngopharynx after endoscopic resection in patients with pharyngeal cancer. However, multiple lugol-voiding lesions in the pharyngeal background mucosa observed during treatment can be used as a biomarker of metachronous multiple cancer, and hence, it would be important to evaluate the pharyngeal background mucosa by lugol staining. Endoscopic surveillance in patients who have undergone radiotherapy for pharyngeal cancer requires the evaluation of additional mucosal injury effect and close attention for laryngeal edema during examination. Metachronous multiple cancer developing after radiotherapy for pharyngeal cancer can also be an indication for endoscopic resection ; however, the treatment encompasses the risk of developing adverse events, such as delayed mucosal healing and local infection. Endoscopic resection would be one of the salvage treatment choices for residual pharyngeal cancer after radiotherapy. Although the treatment involves technical difficulty and the risk of developing adverse events, it can avoid invasive laryngectomy.