2023 Fiscal Year Final Research Report

Research for therapeutic strategies based on molecular and pathological characteristics of gastric cancer in the elderly

Research Project

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Project/Area Number	19K07428
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Review Section	Basic Section 49020:Human pathology-related
Research Institution	Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology
Principal Investigator	Arai Tomio 地方独立行政法人東京都健康長寿医療センター(東京都健康長寿医療センター研究所), 東京都健康長寿医療センター研究所, 研究員 (20232019)
Co-Investigator(Kenkyū-buntansha)	松田陽子香川大学, 医学部, 教授 (20363187)
Project Period (FY)	2019-04-01 – 2024-03-31
Keywords	胃癌 / 高齢者 / 乳頭腺癌 / マイクロサテライト不安定性 / PD-L1 / 免疫チェックポイント阻害剤
Outline of Final Research Achievements	We investigated 336 cases of gastric cancer to clarify clinicopathological characteristics of patients aged 80 years or older. Characteristics observed in the elderly with gastric cancer, such as antral location, elevated gross type, differentiated type, increased number of multiple cancers, and low lymph node metastasis, tended to be more evident in those aged 80 years or older. In addition, 40 cases were analyzed to clarify the molecular pathological characteristics of papillary adenocarcinoma among aged patients with gastric cancer and the indications for immune checkpoint inhibitors. Microsatellite instability (MSI) was observed in 43% of papillary adenocarcinomas. In papillary adenocarcinomas with MSI, there was an association with female gender, lower-stage origin, the presence of mixed poorly differentiated adenocarcinoma components, and the proportion of early-stage cancers. The positive rate of PD-L1 expression was 63%, with a higher positive rate in MSI cases.
Free Research Field	病理学
Academic Significance and Societal Importance of the Research Achievements	胃癌発生は減少傾向にあるとは言え，高齢者においてはまだ重要な疾患である．高齢者胃癌の臨床病理学的および分子病理学的特徴を明らかにすることにより，高齢者胃癌の病態および病因の解明に寄与することができる点に学術的意義がある．また社会的には，学術的なエビデンスに基づき，高齢者胃癌の病態に対応する低侵襲な治療法の選択肢を提示することができる．