外科の立場からみたm3・sm1食道癌

Optimum Treatment for m3・sm1 Esophageal Cancer: The Surgeons' Point of View

要旨　m₃・sm₁食道癌の臨床像を検討し，外科的立場から治療方針を提案した．m₃・sm₁食道癌はEMRと放射線治療によって局所再発を認めなかった．m₃食道癌はリンパ節転移・脈管侵襲はまれであるが(8％，8％)，sm₁食道癌はそれらの頻度が高率であった(36％，50％)．現状ではリンパ節転移の画像診断が必ずしも完全でないため，食道表在癌に対し診断と治療を兼ねてEMRを行い，脈管侵襲を伴わないm₃食道癌にはEMRと必要に応じて放射線治療の追加を，脈管侵襲を伴うm₃食道癌やsm₁食道癌にはリンパ節郭清(3領域郭清)を伴う食道切除術が第1選択として推奨される．

　The purpose of this study was to determine the optimum treatment strategy for a superficial esophageal cancer involving the muscularis mucosa (m₃) or the shallower third of the submucosal layer (sm₁) of the esophagus. The histological findings from the resected specimens, the incidences of lymph node metastasis and recurrence, and the survival rates were retrospectively analysed in 42 cases with an m₃ or sm₁ cancer that underwent esophagectomy, endoscopic mucosal resection (EMR), or radiotherapy, in Kurume University Hospital, during the period from 1981 to 1997. No local recurrence was observed after EMR or radiotherapy for cases with an m₃ or sm₁ cancer. Lymph node metastasis and/or recurrence and lymphatic and/or vascular invasion were rarely observed in cases of an m₃ cancer, while these were frequently observed in cases of an sm₁ cancer. We consider that patients at a high risk to lymph node metastasis should undergo esophagectomy with lymphadenectomy, because preoperative staging of lymph node metastasis has remained incomplete even using the most modern investigative methods. Following an EMR for a superficial esophageal cancer, the depth of invasion, and lymphatic and/or vascular invasion must be confirmed by histological examination of the endoscopically resected specimen. While EMR alone or EMR with the addition of radiotherapy can be sufficient for curative treatment for an m₃ cancer without lymphatic and/or vascular invasion, esophagectomy with lymphadenectomy is recommended as the treatment of first choice for an m₃ cancer with lymphatic and/or vascular invasion and for an sm₁ cancers.