治療成績からみた食道m3・sm癌の治療方針―化学放射線療法（CRT）の治療成績

Chemoradiotherapy for Superficial Esophageal Squamous Cell Carcinoma

要旨　内視鏡的治療の適応を超えたStage I食道癌に対する化学放射線療法（chemoradiotherapy ; CRT）の治療成績について検討した．当院のretrospectiveな解析では，1994年1月から2002年12月までに根治的CRTを行われたStage I食道扁平上皮癌は41例で，その効果はCR率87.8％，1年生存率97.5％，3年生存率79.4％，5年生存率66.9％であった．局所の遺残再発例に対しては，救済治療として内視鏡治療9例，外科切除3例が安全に実施できたが，CR36例中3例（8％）でCRT後の晩期毒性に起因すると思われる死亡が認められた．一方Japan Clinical Oncology Group（JCOG）での多施設共同第II相試験（JCOG9708）でもCR率96％，2年生存率93％と外科切除に匹敵するCRTの有効性が示され，Stage I食道癌に対するCRTの有効性を標準治療である外科切除と比較する第III相試験JCOG0502が間もなく開始予定である．

　Treatment outcomes of definitive chemoradiotherapy for superficial esophageal carcinoma beyond the indications for endoscopic mucosal resection (EMR) were analyzed. There were 41 patients with stage I esophageal squamous cell carcinoma who underwent definitive chemoradiotherapy. Of the 41, 36 (87.8％) patients achieved a complete response with 1-, 3-, and 5-year survival rates of 97.5％, 79.4％, 66.9％, respectively. Salvage treatments, predominantly with EMR, were safely undergone for local residual/recurrent tumors. However, three (8％) of 36 CR patients died without cancer, which event might have been caused by late toxicity. A multi-institutional phase II study of definitive chemoradiotherapy for stage I esophageal cancer (JCOG9708) has resulted in good outcomes with a complete response rate of 96％ and a 2-year survival rate of 93％. These results suggested that chemoradiotherapy might achieve outcomes comparable with radical surgery in this stage. A randomized trial comparing surgery with definitive chemoradiotherapy (JCOG0502) will soon be initiated.