Kunogi Hiroaki, Shimoyachi Nana, Serizawa Itsuko, Kamima Tatsuya, Numao Noboru, Yonese Junji, Yoshioka Yasuo
Department of Radiation Oncology, Cancer Institute Hospital, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan.
Department of Genitourinary Oncology, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo, Japan.
Sci Rep. 2025 Jun 2;15(1):19261. doi: 10.1038/s41598-025-04475-6.
The study aimed to assess the effect of a rectal spacer on the inter-fraction motion of the seminal vesicles (SV) during prostate stereotactic body radiotherapy (SBRT). Clinical data from 60 consecutive patients (300 fractions) with localized prostate cancer treated with definitive SBRT alone (five fractions), between June 2022 and January 2024 were retrospectively reviewed. Of the 60 patients, 44 had a spacer implanted. The residual displacement of SVs in the cone-beam CT relative to those in the planning CT was compared between with and without spacer. The maximum displacement of the proximal SV in 90% of the patients was also evaluated. Additionally, the relationship between the gel/prostate volume ratio and SV displacement was analyzed. The gel/prostate volume ratio was 30 ± 15%. Proximal SV displacement significantly differed with and without the spacer (2.0 vs. 3.8 mm, P < 0.001). Maximum proximal SV displacement also significantly differed with and without the spacer (3.0 vs. 5.1 mm, P < 0.001). In 90% of patients with the spacer, the maximum proximal SV displacement was within 4 mm. SV displacement did not change according to gel/prostate volume ratio. The spacer can limit inter-fraction motion of SVs. The gel/prostate volume ratio was not clinically significant.
本研究旨在评估直肠间隔物对前列腺立体定向体部放疗（SBRT）期间精囊（SV）分次间运动的影响。回顾性分析了2022年6月至2024年1月期间连续60例仅接受确定性SBRT（五分次）治疗的局限性前列腺癌患者（300分次）的临床资料。60例患者中，44例植入了间隔物。比较了有间隔物和无间隔物情况下，锥形束CT中SV相对于计划CT中SV的残余位移。还评估了90%患者近端SV的最大位移。此外，分析了凝胶/前列腺体积比与SV位移之间的关系。凝胶/前列腺体积比为30±15%。有间隔物和无间隔物时近端SV位移有显著差异（2.0对3.8mm，P<0.001）。有间隔物和无间隔物时近端SV最大位移也有显著差异（3.0对5.1mm，P<0.001）。在90%有间隔物的患者中，近端SV最大位移在4mm以内。SV位移未随凝胶/前列腺体积比而变化。间隔物可限制SV的分次间运动。凝胶/前列腺体积比在临床上无显著意义。
