2022 Fiscal Year Final Research Report

Development of optimal treatment schedules of definitive high-precision radiotherapy for cervical cancer

Research Project

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Project/Area Number	19K08179
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Review Section	Basic Section 52040:Radiological sciences-related
Research Institution	University of the Ryukyus
Principal Investigator	Toita Takafumi 琉球大学, 医学(系)研究科(研究院), 客員教授 (30237036)
Co-Investigator(Kenkyū-buntansha)	草田武朗琉球大学, 病院, 客員研究員 (40820973) 有賀拓郎琉球大学, 病院, 特命講師 (60647337) 和田健太郎地方独立行政法人大阪府立病院機構大阪国際がんセンター(研究所), その他部局等, 放射線腫瘍科特別研究員 (90770678) 前本均琉球大学, 病院, 助教 (70774470)
Project Period (FY)	2019-04-01 – 2023-03-31
Keywords	子宮頸癌 / 放射線治療 / 強度変調放射線治療 / 高精度放射線治療 / 低毒性治療
Outline of Final Research Achievements	Because of insufficient clinical data of definitive radiotherapy consisted of IMRT (no central shielding) and 3D-IGBT for Japanese patients, we conducted multi-institutional retrospective observational study to explore the feasibility and appropriate doses for Japanese cervical cancer patients. The study included 167 patients (T1+2 = 108, T3+4 = 59) from 8 Japanese institutions. The 2-year incidence of >=grade 3 proctitis/cystitis was 4%/1% for T1+2 and 10%/2% for T3+4. The 2-year local progression-free survival (LPFS) was 89% for T1+2 and 82% for T3+4. For T1+2, the 2-year LPFS for HR-CTV D90 >=68 Gy was 92% versus 67% for <68 Gy (log-rank; P = 0.019). For T3+4, the 2-year LPFS was 87% for HR-CTV <82 cm3 and 43% for >=82 cm3 (P = 0.0004). In conclusion, definitive radiotherapy consisting of no-CS-EBRT and 3D-IGBT was feasible for Japanese patients with cervical cancer. Dose de-escalation from the current global standards is suggested for patients with T1+2 disease.
Free Research Field	放射線腫瘍学
Academic Significance and Societal Importance of the Research Achievements	本邦で遅れていた高精度放射線治療の強度変調放射線治療（IMRT）の子宮頸癌根治照射への適用に向けた研究の推進に寄与する。欧米の標準線量より低線量で腫瘍制御が可能な患者群が示唆されたことにより、日本人をはじめアジア人女性に対しより安全な低毒性治療が可能になることが期待される。