Houlihan Orla Anne, Rangaswamy Guhan, Dunne Mary, Rohan Christine, O'Neill Louise, Chalke Shelton, Daly Patricia, Gillham Charles, McArdle Orla
St. Luke's Radiation Oncology Network, Dublin, Ireland.
BJR Open. 2021 Feb 3;3(1):20200067. doi: 10.1259/bjro.20200067. eCollection 2021.
Radiotherapy plays an important role in the management of lymphoma and many patients with lymphoma are cured with treatment. Risk of secondary malignancy and long-term cardiac and pulmonary toxicity from mediastinal radiotherapy exists. Delivery of radiotherapy using a deep inspiration breath-hold (DIBH) technique increases lung volume and has the potential to reduce dose to heart and lungs. We undertook a prospective study to assess the dosimetric differences in DIBH and free breathing (FB) plans in patients requiring mediastinal radiotherapy in clinical practice.
We performed both FB and DIBH planning scans on 35 consecutive patients with mediastinal lymphoma needing radiotherapy. Contours and plans were generated for both data sets and dosimetric data were compared. All patients were planned using volumetric modulated arc therapy (VMAT). Data were compared for FB and DIBH plans with each patient acting as their own control using the related-samples Wilcoxon signed rank test.
DIBH significantly reduced lung doses (mean 10.6 11.4Gy, < 0.0005; V20 16.8 18.3%, = 0.001) and spinal cord maximum dose (20.6 22.8Gy, = 0.001). DIBH increased breast V4 (38.5% 31.8%, = 0.006) and mean right breast dose (4.2 3.6Gy, = 0.010). There was no significant difference in heart doses when the entire study cohort was considered, however, mean heart dose tended to be lower with DIBH for upper mediastinal (UM) tumours (4.3 4.9Gy, = 0.05).
Our study describes the potential benefit of DIBH in a population reflective of clinical practice. DIBH can decrease radiation dose to lungs, heart and spinal cord, however, may increase dose to breasts. DIBH is not always superior to FB, and the clinical significance of differences in dose to organs at risk in addition to the time required to treat patients with DIBH must be considered when deciding the most appropriate radiotherapy technique for each patient.
To our knowledge, this is the largest study comparing DIBH and FB planning for patients with lymphoma receiving mediastinal radiotherapy in clinical practice. It demonstrates the impact of an increasingly common radiotherapy technique on dose to organs at risk and the subsequent potential for long-term radiotherapy side-effects.
放射治疗在淋巴瘤的治疗中发挥着重要作用，许多淋巴瘤患者通过治疗得以治愈。存在继发恶性肿瘤的风险以及纵隔放疗导致的长期心脏和肺部毒性。采用深吸气屏气（DIBH）技术进行放射治疗可增加肺容积，并有可能降低心脏和肺部的剂量。我们进行了一项前瞻性研究，以评估临床实践中需要纵隔放疗的患者在DIBH和自由呼吸（FB）计划中的剂量差异。
我们对35例连续的需要放疗的纵隔淋巴瘤患者进行了FB和DIBH计划扫描。为两个数据集生成轮廓和计划，并比较剂量学数据。所有患者均采用容积调强弧形放疗（VMAT）进行计划。使用相关样本Wilcoxon符号秩检验，将FB和DIBH计划的数据进行比较，每位患者作为自身对照。
DIBH显著降低了肺剂量（平均10.6±11.4Gy，P<0.0005；V20为16.8±18.3%，P = 0.001）和脊髓最大剂量（20.6±22.8Gy，P = 0.001）。DIBH增加了乳腺V4（38.5%±31.8%，P = 0.006）和右乳腺平均剂量（4.2±3.6Gy，P = 0.010）。当考虑整个研究队列时，心脏剂量没有显著差异，但对于上纵隔（UM）肿瘤，DIBH的平均心脏剂量往往较低（4.3±4.9Gy，P = 0.05）。
我们的研究描述了DIBH在反映临床实践的人群中的潜在益处。DIBH可降低对肺、心脏和脊髓的辐射剂量，然而，可能会增加对乳腺的剂量。DIBH并不总是优于FB，在为每位患者确定最合适的放疗技术时，除了DIBH治疗患者所需的时间外，还必须考虑对危及器官剂量差异的临床意义。
据我们所知，这是在临床实践中比较接受纵隔放疗的淋巴瘤患者DIBH和FB计划最大的研究。它证明了一种日益常见的放疗技术对危及器官剂量的影响以及随后长期放疗副作用的可能性。
