Establishment of non-invasive evaluation of tumor aggressiveness of prostate cancer using prostate multiparametric MR imaging

• Project/Area Number: 15K09940
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Radiation science
• Research Institution: Kawasaki Medical School
• Principal Investigator: Tamada Tsutomu 川崎医科大学, 医学部, 教授 (40278932)
• Co-Investigator(Kenkyū-buntansha): 伊東 克能 山口大学, 大学院医学系研究科, 教授 (00274168) ; 鹿股 直樹 川崎医科大学, 医学部, 准教授 (60263373) ; 曽根 照喜 川崎医科大学, 医学部, 教授 (90179383)
• Research Collaborator: Jo yoshimasa
• Project Period (FY): 2015-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000); Fiscal Year 2017: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000); Fiscal Year 2016: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000); Fiscal Year 2015: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
• Keywords: 前立腺癌 / 磁気共鳴画像 / マルチパラメトリックMRI / 拡散強調像 / 悪性度 / グリーソンスコア / 前立腺有意癌 / MRI / 拡散強調画像

Outline of Final Research Achievements

Multiparametric magnetic resonance imaging (T2-weighted, diffusion-weighted, and dynamic contrast-enhanced imaging) of the prostate is regarded as an effective method for detecting highly malignant, clinically significant prostate cancer requiring treatment. However, as yet there are no established methods for accurately evaluating the tumor aggressiveness. In this study, we first calculated quantitative indices for tumors from the above-mentioned three imaging modalities, and investigated their associations with tumor aggressiveness using the Gleason score, an index of pathological malignancy. We found that the index highly associated with tumor aggressiveness was the apparent diffusion coefficient (ADC), calculated from diffusion-weighted images. The ADC was also better at distinguishing the tumor aggressiveness than kurtosis, another quantitative index calculated from diffusion-weighted images. We showed that the ADC offers a useful prognostic factor for untreated prostate cancer.

Academic Significance and Societal Importance of the Research Achievements

前立腺MRIを用いて治療が必要な悪性度の高い前立腺有意癌を検出する際に、視覚的な画像評価ではなく拡散強調像から得られるみかけの拡散係数（ADC）を加えて評価することでより正確に前立腺有意癌を診断することできる。また治療の必要の無い前立腺非有意癌と鑑別することもできる。さらに前立腺癌の最終診断は前立腺に針を刺して組織を採取（生検）し病理組織学的に行われるが、生検前にMRIを施行し腫瘍部のADCの評価によって悪性度が高いと診断された病変を標的として生検することによって前立腺有意癌の検出能が従来の系統的生検（前立腺の決まった場所のみ生検する方法）に比して格段に改善することが期待される。

Research Products

• [Journal Article] Multidimensional analysis of clinicopathological characteristics of false-negative clinically significant prostate cancers on multiparametric MRI of the prostate in Japanese men. (2019)
  • Author(s): Kido A, Tamada T, Kanomata N, Yamamoto A, Miyaji Y, Nagai A, Sone T.
  • Journal Title: Jpn J Radiol Volume: 37 Issue: 2 Pages: 154-164
  • DOI: 10.1007/s11604-018-0801-9
  • NAID: 50013148782
  • Peer Reviewed
• [Presentation] Clinicopathological Characteristics of False-Negative Clinically Significant Prostate Cancers on Multiparametric MRI (2018)
  • Author(s): Ayumu Kido, Tsutomu Tamada, Naoki Kanomata, Hidemitsu Sotozono, Takeshi Fukunaga, Akihiko Kanki, Akira Yamamoto
  • Organizer: RSNA 2018
  • Int'l Joint Research
• [Presentation] PSA監視療法中の前立腺癌の進行を予測 するためのwhole-lesion apparent diffusion coefficient解析の役割 (2018)
  • Author(s): 玉田 勉 他
  • Organizer: 第106回日本泌尿器科学会総会
• [Presentation] Diffusion-weighted MR Imaging for Detection and Assessment of Aggressiveness of Prostate Cancer: Comparison Between Conventional and Kurtosis Models (2017)
  • Author(s): 玉田 勉 他
  • Organizer: SAR 2017 (Society of Abdominal Radiology)
  • Place of Presentation: 米国 フロリダ
  • Year and Date: 2017-03-26
  • Int'l Joint Research
• [Presentation] 前立腺癌組織の画像解析データと，MRI画像パラメータとの比較解析 (2016)
  • Author(s): 鹿股直樹、玉田 勉、鈴木聡一郎、稲吉貴絵、宮地禎幸、森谷卓也
  • Organizer: 第105回 日本病理学会総会
  • Place of Presentation: 仙台国際センター会議棟・展示棟（仙台）
  • Year and Date: 2016-05-12