Barrett食道腺癌内視鏡的切除後の長期予後—LSBEを中心に

The Long-term Prognosis after Endoscopic Submucosal Dissection of Esophageal Adenocarcinoma Arising from Barrett's Esophagus:Focusing on Long-Segment Barrett's Esophagus

要旨●2000年1月〜2017年9月までに当院でESDを施行したLSBE（プラハ分類M3以上）由来の腺癌のうち，3年以上経過観察が施行された16例20病変（経過観察期間中央値128か月）を対象とし長期予後を検討した．結果は腫瘍径中央値36mm，切除径中央値86mmであった．主病変の深達度はT1a-SMM 1例，T1a-LPM 1例，T1a-DMM 12例，T1b-SM1 2例であった．組織型はいずれも分化型であった．一括完全切除率は95％で，脈管侵襲（ly，v）はいずれも陰性であった．16例中4例で各1つずつの同時多発癌（25％）を認めた．16例中7例に全周切除を，9例に局所切除を施行した．全周切除例では異時多発癌を認めず，Barrett粘膜の再発も認めなかった．局所切除9例のうち6例は経過観察し，うち2例（33％）で異時多発癌を認めた．異時多発癌を認めた2例では残Barrett粘膜が3cm以上と長く，異時多発癌を認めなかった4例では残Barrett粘膜が3cm未満と短かった．したがって，残Barrett粘膜の面積が広い（M3以上つまりLSBE）ほど異時多発癌を来しうることが推察された．また局所切除した残りの3例は，異時多発癌の予防目的で，残Barrett粘膜に対しstepwise ESDを施行した．3例とも術後狭窄やBarrett粘膜の再発はなく，stepwise ESDは異時多発癌の抑制に有用であった．ESDにて加療したLSBE由来のEAC 16例に原病死はなく，疾患特異的生存率は3年，5年ともに100％であった．また，全生存率は3年，5年ともに100％であった．

　Among the adenocarcinomas arising from long-segment Barrett's esophagus（LSBE; Prague classification M3 or longer）treated by ESD（endoscopic submucosal dissection）during the period from January 2000 to September 2017 at our hospital, we included 20 lesions in 16 patients with a confirmed follow-up of 3 years or more（median follow-up observation period of 128 months）.

　The median tumor diameter was 36mm, and the median resected specimen diameter was 86mm. The invasion depth of the primary lesion was T1a-SMM in 1 patient, T1a-LPM in 1 patient, T1a-DMM in 12 patients, and T1b-SM1 in 2 patients. The histological types were differentiated in all patients. The rate of en bloc resection was 95%, and all patients were negative for vascular invasion（ly, v）. Four of the 16 patients presented with a synchronous multiple cancers（25%）.

　Of the 16 patients, circumferential and localized resection were performed in 7 and 9 patients, respectively. Patients who underwent circumferential resection did not have not only metachronous cancers but also recurrence of Barrett's esophagus. In six of the nine patients who underwent localized resection, follow-up was performed, and two of these patients（33%）exhibited metachronous cancers. In these two patients, residual Barrett's mucosa was ≥3cm in length, and in the remaining four patients who did not have metachronous cancers, residual Barrett's mucosa was short（<3cm）. Therefore, large residual Barrett's mucosa（M3 or longer）was a risk factor of metachronous cancer.

　In the remaining three patients who underwent localized resection, stepwise ESD was performed for the residual Barrett's mucosa to prevent metachronous cancers. In these three patients, no postoperative stenosis or recurrence of Barrett's mucosa was observed.

　In the 16 patients with esophageal adenocarcinoma arising from LSBE who were treated by ESD, there was no death from the underlying illness, and the disease-specific survival rates at 3 and 5 years were 100%. Furthermore, the overall survival rates at 3 years and 5 years were also 100%.