Department of Radiation Oncology, Azienda Sanitaria Universitaria Integrata di Trieste, Trieste, Italy.
Department of Medical Physics, Azienda Sanitaria Universitaria Giuliano-Isontina, Trieste, Italy.
Radiol Oncol. 2021 May 16;55(3):333-340. doi: 10.2478/raon-2021-0023.
Breast intraoperative electron radiation therapy (B-IOERT) can be used in clinical practice both as elective irradiation (partial breast irradiation - APBI) in low risk breast cancer patients, and as an anticipated boost. The procedure generally includes the use of a shielding disk between the residual breast and the pectoralis fascia for the protection of the tissues underneath the target volume. The aim of the study was to evaluate the role of intraoperative ultrasound (IOUS) in improving the quality of B-IOERT.
B-IOERT was introduced in Trieste in 2012 and its technique was improved in 2014 with IOUS. Both, needle and IOUS were used to measure target thickness and the latter was used even to check the correct position of the shielding disk. The primary endpoint of the study was the evaluation of the effectiveness of IOUS in reducing the risk of a disk misalignment related to B-IOERT and the secondary endpoint was the analysis of acute and late toxicity, by comparing two groups of patients treated with IOERT as a boost, either measured with IOUS and needle (Group 1) or with needle alone (Group 2). Acute and late toxicity were evaluated by validated scoring systems.
From the institutional patients who were treated between June 2012 and October 2019, 109 were eligible for this study (corresponding to 110 cases, as one patients underwent bilateral conservative surgery and bilateral B-IOERT). Of these, 38 were allocated to group 1 and 72 to group 2. The target thickness measured with the IOUS probe and with the needle were similar (mean difference of 0.1 mm, p = 0.38). The percentage of patients in which the shield was perfectly aligned after IOUS introduction increased from 23% to more than 70%. Moreover, patients treated after IOUS guidance had less acute toxicity (36.8% . 48.6%, p = 0.33) from radiation therapy, which reached no statistical significance. Late toxicity turned out to be similar regardless of the use of IOUS guidance: 39.5% vs. 37.5% (p = 0.99).
IOUS showed to be accurate in measuring the target depth and decrease the misalignment between collimator and disk. Furthermore there was an absolute decrease in acute toxicity, even though not statistically significant, in the group of women who underwent B-IOERT with IOUS guidance.
乳腺术中电子放射治疗（B-IOERT）可在临床实践中用于低危乳腺癌患者的选择性照射（部分乳腺照射-APBI），也可作为预期的增敏。该过程通常包括在残留乳房和胸大肌筋膜之间使用屏蔽盘，以保护靶体积下方的组织。本研究的目的是评估术中超声（IOUS）在提高 B-IOERT 质量方面的作用。
B-IOERT 于 2012 年在的里雅斯特引入，并于 2014 年通过 IOUS 改进了其技术。针和 IOUS 均用于测量目标厚度，后者甚至用于检查屏蔽盘的正确位置。该研究的主要终点是评估 IOUS 在降低与 B-IOERT 相关的磁盘错位风险方面的有效性，次要终点是通过比较两组接受 IOERT 作为增敏的患者来分析急性和迟发性毒性，这两组患者的治疗均使用 IOUS 和针（组 1）或仅使用针（组 2）进行测量。急性和迟发性毒性通过经过验证的评分系统进行评估。
从 2012 年 6 月至 2019 年 10 月接受治疗的机构患者中，有 109 例符合本研究条件（对应 110 例，因为一名患者接受了双侧保乳手术和双侧 B-IOERT）。其中，38 例患者被分配到组 1，72 例患者被分配到组 2。使用 IOUS 探头和针测量的目标厚度相似（平均差值为 0.1mm，p=0.38）。在引入 IOUS 后，屏蔽完全对齐的患者比例从 23%增加到 70%以上。此外，接受 IOUS 引导治疗的患者接受放射治疗后的急性毒性反应（36.8%比 48.6%，p=0.33）较低，但未达到统计学意义。迟发性毒性无论是否使用 IOUS 指导，结果均相似：39.5%比 37.5%（p=0.99）。
IOUS 可准确测量靶深度，并减少准直器和磁盘之间的错位。此外，在接受 IOUS 引导的 B-IOERT 治疗的女性中，急性毒性反应绝对降低，尽管无统计学意义。
