Consideration of appropriate use of immune checkpoint inhibitors in esophageal cancer using ctDNA

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K15575
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 50020:Tumor diagnostics and therapeutics-related
• Research Institution: Iwate Medical University
• Principal Investigator: Nikai Haruka 岩手医科大学, 医学部, 助教 (90750860)
• Project Period (FY): 2021-04-01 – 2023-03-31
• Keywords: ICI / Nivolumab / Circulating tumor DNA / Esophageal cancer

Outline of Final Research Achievements

In this study, we conducted predictive analysis of the effectiveness of ICI therapy using ctDNA. Similar to conventional chemotherapy, cases where ctDNA decreased after one cycle of ICI therapy showed a favorable response and prolonged effects. Conversely, in cases with rapid ctDNA increase, early progression was observed. In cases where there was uncertainty about continuing treatment despite mild progression, ctDNA showed early elevation, followed by clear enlargement on imaging.

Based on the above, ctDNA monitoring using dPCR demonstrated the potential to overcome the limitations of imaging-based diagnostic evaluations, such as early assessment of treatment efficacy and early detection of hyperprogressive disease (HPD), making it an important diagnostic tool for immunotherapy with checkpoint inhibitors in esophageal cancer.

Free Research Field

Esophageal cancer

Academic Significance and Societal Importance of the Research Achievements

ICI治療では従来の化学療法とは異なった治療経過をたどることがあり、迅速かつ正確に腫瘍細胞量を判定し、治療効果判定とすることがICI適正使用のために必要であると思われる。ctDNAによる効果判定は画像による炎症反応を含んだ腫瘍サイズによる判定と異なり、遺残癌細胞量を示すものであり、より客観的指標である。本研究の成果は、ctDNAによる早期治療効果判定、HPDの早期発見など画像診断評価の弱点を克服する重要な検査ツールとなる可能性を示した。