Aims

The aim of TROG 14.04 was to assess the feasibility of deep inspiration breath hold (DIBH) and its impact on radiation dose to the heart in patients with left-sided breast cancer undergoing radiotherapy. Secondary end points pertained to patient anxiety and cost of delivering a DIBH programme.

Materials and methods

The study comprised two groups – left-sided breast cancer patients engaging DIBH and right-sided breast cancer patients using free breathing through radiotherapy. The primary end point was the feasibility of DIBH, defined as left-sided breast cancer patients' ability to breath hold for 15 s, decrease in heart dose in DIBH compared with the free breathing treatment plan and reproducibility of radiotherapy delivery using mid-lung distance (MLD) assessed on electronic portal imaging as the surrogate. The time required for treatment delivery, patient-reported outcomes and resource requirement were compared between the groups.

Results

Between February and November 2018, 32 left-sided and 30 right-sided breast cancer patients from six radiotherapy centres were enrolled. Two left-sided breast cancer patients did not undergo DIBH (one treated in free breathing as per investigator choice, one withdrawn). The mean heart dose was reduced from 2.8 Gy (free breathing) to 1.5 Gy (DIBH). Set-up reproducibility in the first week of treatment assessed by MLD was 1.88 ± 1.04 mm (average ± 1 standard deviation) for DIBH and 1.59 ± 0.93 mm for free breathing patients. Using a reproducibility cut-off for MLD of 2 mm (1 standard deviation) as per study protocol, DIBH was feasible for 67% of DIBH patients. Radiotherapy delivery using DIBH took about 2 min longer than for free breathing. Anxiety was not significantly different in DIBH patients and decreased over the course of treatment in both groups.

Conclusion

Although DIBH was shown to require about 2 min longer per treatment slot, it has the potential to reduce heart dose in left-sided breast cancer patients by nearly a half, provided careful assessment of breath hold reproducibility is carried out.

中文翻译：

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TROG 14.04：乳腺癌患者 DIBH 焦虑的可行性和影响的多中心研究

目标

TROG 14.04 的目的是评估深吸气屏气 (DIBH) 的可行性及其对接受放射治疗的左侧乳腺癌患者心脏辐射剂量的影响。次要终点与患者焦虑和提供 DIBH 计划的成本有关。

材料和方法

该研究包括两组——左侧乳腺癌患者参与 DIBH，右侧乳腺癌患者通过放射治疗进行自由呼吸。主要终点是 DIBH 的可行性，定义为左侧乳腺癌患者屏气 15 秒的能力，与自由呼吸治疗计划相比，DIBH 的心脏剂量减少，以及使用中肺距离进行放射治疗的可重复性（MLD）评估电子门户成像作为替代。比较了各组之间治疗交付所需的时间、患者报告的结果和资源需求。

结果

2018 年 2 月至 2018 年 11 月，来自六个放射治疗中心的 32 名左侧和 30 名右侧乳腺癌患者入组。两名左侧乳腺癌患者未接受 DIBH（一名根据研究者的选择进行自由呼吸治疗，一名退出）。平均心脏剂量从 2.8 Gy（自由呼吸）降低到 1.5 Gy (DIBH)。通过 MLD 评估的治疗第一周的设置再现性对于 DIBH 为 1.88 ± 1.04 mm（平均 ± 1 个标准偏差），对于自由呼吸患者为 1.59 ± 0.93 mm。根据研究方案，使用 2 mm（1 个标准偏差）的 MLD 的可重复性截止值，DIBH 对 67% 的 DIBH 患者是可行的。使用 DIBH 进行放射治疗的时间比自由呼吸的时间长约 2 分钟。

结论

尽管 DIBH 显示每个治疗时间需要大约 2 分钟的时间，但它有可能将左侧乳腺癌患者的心脏剂量减少近一半，前提是对屏气可重复性进行仔细评估。