Establishment of a new colorectal cancer depth diagnostic method using tomosynthesis

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K15848
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 52040:Radiological sciences-related
• Research Institution: Nara Medical University
• Principal Investigator: ITOH TAKAHIRO 奈良県立医科大学, 医学部, 講師 (60285369)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 大腸癌深達度診断 / トモシンセシス / 注腸X線診断

Outline of Final Research Achievements

The usefulness of tomosynthesis (digital tomography) in preoperative depth diagnosis of colorectal cancer was investigated. In principle, early-stage colorectal cancer with a depth of the mucosal layer and up to 1 mm within the submucosal layer (T1a) should be treated endoscopically, and beyond that (T1b) surgical treatment should be performed. Tomosynthesis was used to evaluate the angle of rise and lateral deformation of lesions in 50 cases of early-stage colorectal cancer with confirmed depth by surgery or endoscopic resection: the average angle of rise of T1b cancers was 29° and lateral deformation was arc-shaped in 33 of 43 cases. Comparison with conventional imaging on a five-point scale in terms of visibility showed that the method was superior to the conventional method in 20 out of 43 cases and was judged inferior in only one case.

Free Research Field

放射線医学

Academic Significance and Societal Importance of the Research Achievements

がん死亡原因の上位を占める大腸癌の治療方針決定において、特に内視鏡治療と外科的治療の境目となるT1b（SM高度浸潤癌；SM浸潤距離1000ミクロン以上）の判定はきわめて重要である。内視鏡診断が高度に進歩した現在においても大腸癌治療ガイドライン2022年版においてはcT1高度浸潤癌の診断指標として内視鏡所見以外にX線造影検査を参考にする旨が記載されている。ただし、その検査手技・診断能力の修得には熟練を要するだけでなく、受検者の身体能力が求められる内容であり、高齢化が進んだ現在、低侵襲で詳細かつ簡便な診断が可能となるトモシンセシスを活用したX線検査法の果たす役割は重要と考えられる。