Development of a novel multidisciplinary treatment approach for liver tumors utilizing compensatory liver hypertrophy induced by carbon-ion radiotherapy

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K08728
• 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: Gunma University
• Principal Investigator: Shibuya Kei 群馬大学, 大学院医学系研究科, 講師 (50511490)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 肝腫瘍 / 放射線治療 / 粒子線治療 / 代償性肝肥大 / 集学的治療

Outline of Final Research Achievements

In an in vivo rat model, partial liver irradiation induced compensatory liver hypertrophy in non-irradiated lobes, similar to portal vein embolization (PVE). Increased hepatocyte proliferation contributed to the mechanism of compensatory hypertrophy. Blood biochemistry tests 12 weeks post-irradiation showed no clear deterioration of liver function, suggesting compensatory hypertrophy helps maintain liver functional reserve. Clinical studies indicated the threshold for hepatocyte damage from carbon ion beams is much higher than X-rays when liver function is preserved, implying superiority in conserving liver function during treatment. However, contrary to expectations, no clear correlation was found between the irradiated area exceeding the threshold dose and liver hypertrophy.

Free Research Field

放射線医学

Academic Significance and Societal Importance of the Research Achievements

重粒子線治療を含む放射線治療が有意な代償性肝肥大を引き起こすことが確認され、代償性肝肥大と強力な抗腫瘍効果を併せ持つ新たな術前治療としての可能性が示された。臨床例の検討により、重粒子線照射による肝細胞障害の閾値が古典的な生物学的効果比から算出されるレベルよりも高かったことから、重粒子線治療が生物学的にも肝機能の温存に有利である可能性が示唆された。重粒子線治療と切除を組み合わせた集学的治療につながる知見となることが期待される。