Development of hypofractionated volumetric-modulated dynamic Wave Arc therapy for high-risk prostate cancer

2019 Fiscal Year Final Research Report

• Project/Area Number: 16K10390
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Radiation science
• Research Institution: Kyoto University
• Principal Investigator: MIZOWAKI TAKASHI 京都大学, 医学研究科, 教授 (90314210)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: 放射線治療 / 前立腺癌 / 寡分割照射 / 強度変調放射線治療 / ダイナミックウエーブアーク照射 / 定位照射

Outline of Final Research Achievements

To improve treatment outcomes, shorten the overall treatment period, and reduce toxicities of external-beam radiotherapy for high-risk prostate cancer, we developed a clinical protocol of hypofractionated volumetric-modulated dynamic Wave Arc therapy.
We established a clinical protocol of simultaneously delivering 57 Gy to the primary focuses depicted on MRI and 54 Gy to the whole prostate, respectively, using the simultaneously integrated-boost technique. Then, the accuracy of the irradiation was confirmed by conducting experimental irradiation by phantom studies.
A pilot clinical study of the above-developed irradiation protocol was created, and conducted with the approval of the local ethical committee (approval number: C1388). As of March 31, 2020, 19 patients out of the scheduled registration number of 25 were registered on the clinical study. So far, no recurrence nor severe adverse events have been observed.

Free Research Field

放射線腫瘍学

Academic Significance and Societal Importance of the Research Achievements

寡分割照射は、患者の利便性、医療者の負荷や医療費の低減に大きく寄与する。低～中リスク前立腺癌においては、複数の非劣性試験によって非劣性が証明され、現在では標準治療の位置づけとなりつつある。
一方、高リスク前立腺癌における寡分割照射の有用性を示すエビデンスは未だ少ない。加えて、高リスク癌の治療成績は満足できるものではなく改善の余地が大きく、局所再発が前立腺内の主腫瘍部分から多く起こることが問題の一つである。このような中、本研究は、高リスク前立腺癌に対し寡分割照射化と局所制御率の改善の両立を目指せる可能性を示した点において、学術的意義並びに社会的意義が大きいと考えられる。