食管癌患者长疗程分次磁共振引导放化疗的临床实施与可行性：技术创新的R-IDEAL 1b/2a期评估

Clinical implementation and feasibility of long-course fractionated MR-guided chemoradiotherapy for patients with esophageal cancer: An R-IDEAL stage 1b/2a evaluation of technical innovation.

作者信息

Boekhoff M R, Bouwmans R, Doornaert P A H, Intven M P W, Lagendijk J J W, van Lier A L H M W, Rasing M J A, van de Ven S, Meijer G J, Mook S

机构信息

Department of Radiation Oncology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, the Netherlands.

出版信息

Clin Transl Radiat Oncol. 2022 Mar 17;34:82-89. doi: 10.1016/j.ctro.2022.03.008. eCollection 2022 May.

DOI:10.1016/j.ctro.2022.03.008

PMID:35372703

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC8971577/

Abstract

PURPOSE

This R-Ideal stage 1b/2a study describes the workflow and feasibility of long-course fractionated online adaptive MR-guided chemoradiotherapy with reduced CTV-to-PTV margins on the 1.5T MR-Linac for patients with esophageal cancer.

METHODS

Patients with esophageal cancer scheduled to undergo chemoradiation were treated on a 1.5T MR-Linac. Daily MR-images were acquired for online contour adaptation and replanning. Contours were manually adapted to match the daily anatomy and an isotropic CTV-to-PTV margin of 6 mm was applied. Time was recorded for all individual steps in the workflow. Feasibility and patient tolerability were defined as on-table time of ≤60 min and completion of >95% of the fractions on the MR-Linac, respectively. Positioning verification and post-treatment MRIs were retrospectively analyzed and dosimetric parameters were compared to standard non-adaptive conventional treatment plans.

RESULTS

Nine patients with esophageal cancer were treated with chemoradiation; eight patients received 41.4 Gy in 23 fractions and one received 50.4 Gy in 28 fractions. Four patients received all planned fractions on the MR-Linac, whereas for two patients >5% of fractions were rescheduled to a conventional linac for reasons of discomfort. A total of 183 (86%) of 212 scheduled fractions were successfully delivered on the MR-Linac. Three fractions ended prematurely due to technical issues and 26 fractions were rescheduled on a conventional linac due to MR-Linac downtime (n = 10), logistical reasons (n = 3) or discomfort (n = 13).The median time per fraction was 53 min (IQR = 3 min). Daily adapted MR-Linac plans had similar target coverage, whereas dose to the organs-at-risk was significantly reduced compared to conventional treatment (26% and 12% reduction in mean lung and heart dose, respectively).

CONCLUSION

Daily online adaptive fractionated chemoradiotherapy with reduced PTV margins is moderately feasible for esophageal cancer and results in better sparing of heart and lungs. Future studies should focus on further optimization and acceleration of the current workflow.

摘要

目的

本R-Ideal 1b/2a期研究描述了在1.5T MR直线加速器上对食管癌患者进行长疗程分次在线自适应磁共振引导的放化疗且缩小临床靶体积（CTV）至计划靶体积（PTV）边界的工作流程及可行性。

方法

计划接受放化疗的食管癌患者在1.5T MR直线加速器上接受治疗。每日采集磁共振图像用于在线轮廓调整和重新计划。轮廓手动调整以匹配每日解剖结构，并应用6mm的各向同性CTV至PTV边界。记录工作流程中所有单个步骤的时间。可行性和患者耐受性分别定义为治疗台上时间≤60分钟以及在MR直线加速器上完成>95%的分次治疗。对定位验证和治疗后磁共振成像进行回顾性分析，并将剂量学参数与标准非自适应传统治疗计划进行比较。

结果

9例食管癌患者接受了放化疗；8例患者接受23次分次照射，剂量为41.4Gy，1例患者接受28次分次照射，剂量为50.4Gy。4例患者在MR直线加速器上完成了所有计划的分次治疗，而2例患者因不适，>5%的分次治疗被重新安排至传统直线加速器。212次计划分次中有183次（86%）在MR直线加速器上成功完成。3次分次因技术问题提前结束，26次分次因MR直线加速器停机（n = 10）、后勤原因（n = 3）或不适（n = 13）被重新安排至传统直线加速器。每次分次的中位时间为53分钟（四分位间距 = 3分钟）。每日调整后的MR直线加速器计划具有相似的靶区覆盖，而与传统治疗相比，危及器官的剂量显著降低（平均肺剂量和心脏剂量分别降低26%和12%）。