Improved survival by Helicobacter pylori-modulated immunity in gastric cancer patients with adjuvant chemotherapy

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K09130
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 55020:Digestive surgery-related
• Research Institution: Iwate Medical University
• Principal Investigator: Koeda Keisuke 岩手医科大学, 医学部, 教授 (10285596)
• Co-Investigator(Kenkyū-buntansha): 西塚 哲 岩手医科大学, 医歯薬総合研究所, 特任教授 (50453311)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 胃がん / Helicobacter pylori / 術後補助化学療法 / 免疫応答

Outline of Final Research Achievements

Paradoxically, Helicobacter pylori-positive gastric cancer patients have a better prognosis than those who are HP-negative. Immunologic and statistical analyses can be used to verify whether systematic mechanisms modulated by HP are involved in this more favorable outcome. A total of 658 advanced 6gastric cancer patients who underwent gastrectomy were enrolled. HP infection and programmed death-ligand 1 (PD-L1) were analyzed. Among 491 cases that were analyzed, analysis of RFS indicated an interaction of HP status among the subgroups for S-1 Dose and PD-L1. HP+ patients in the PD-L1 group had significantly higher five-year OS and RFS than HP- patients. Thus, HP status was identified as one of the most potentially important independent factors to predict prolonged survival. Modulation of host immune system function by HP may contribute to prolonged survival in the absence of immune escape mechanisms of gastric cancer.

Free Research Field

消化器外科

Academic Significance and Societal Importance of the Research Achievements

胃がん発症のリスク因子として知られているHelicobacter pylori(HP)感染が、進行胃癌患者では逆説的に予後が良いことが各国から報告されている。我々も同様の結果を報告してきたが、今回HP感染と免疫応答の関連、特に術後補助化学療法の効果に着目し研究を行った。
結果、PD-L1陰性かつHP陽性症例において術後補助化学療法の効果が強く認められていることが明らかになった。今後手術検体より術後補助化学療法の効果および予後予測が可能となり、治療のオーダーメード化に繋がる事が期待される。