Study of exfoliated tumor cells and local recurrence after colorectal endoscopic submucosal dissection

2019 Fiscal Year Final Research Report

• Project/Area Number: 18K16326
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 55020:Digestive surgery-related
• Research Institution: Nara Medical University
• Principal Investigator: Inoue Takashi 奈良県立医科大学, 医学部, 助教 (60623478)
• Project Period (FY): 2018-04-01 – 2020-03-31
• Keywords: 大腸粘膜下層剥離術 / 遊離腫瘍細胞 / 局所再発 / viability / povidone iodine / implantation / 遺伝子変異 / 腸管内洗浄

Outline of Final Research Achievements

The viability of exfoliated tumor cells in intraluminal lavage samples after 15 colorectal endoscopic submucosal dissection were measured. The viability did not decrease over time, at the end of ESD, 3 hours, 6 hours, and 12 hours after ESD. However, the viability did significantly decrease, when 2 % povidone iodine were added.DNA samples were extracted from resected tumors and exfoliated tumor cells in intraluminal lavage samples with positive cytology. Each extracted sample was analyzed by next gene sequencer. Evaluation of gene mutations between resected tumors and exfoliated tumor cells showed 100% concordance in two patients and 94.3% concordance in two patients in the screening of 19 gene mutations.

Free Research Field

消化器外科学

Academic Significance and Societal Importance of the Research Achievements

今まで内視鏡治療後における局所再発の機序は証明されていなかったが、今回大腸ESDで切除した腫瘍とESD後の洗浄液中の遊離腫瘍細胞の遺伝子変異の一致率が高く、従来の内視鏡治療よりも比較的長時間の腫瘍に対する物理的刺激を伴うESD操作にて腫瘍から細胞が腸管内に遊離したと考えられ、その遊離腫瘍細胞はviabilityを持っており、大腸ESD後の局所再発の機序がimplantationであることを裏付ける結果となった。遊離腫瘍細胞のviabilityは時間経過では低下せず、消毒液付加で低下したため、大腸ESD後に消毒液を付加した液で洗浄することで大腸ESD後の局所再発の予防につながると考えられた。