Hou Pei-Yu, Hsieh Chen-Hsi, Wu Le-Jung, Hsu Chen-Xiong, Kuo Deng-Yu, Lu Yueh-Feng, Tien Hui-Ju, Hsiao Hsiu-Wen, Shueng Pei-Wei, Hsu Shih-Ming
Department of Radiation Oncology, Far Eastern Memorial Hospital, Taipei 220, Taiwan.
Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Taipei 30010, Taiwan.
Cancers (Basel). 2021 Oct 9;13(20):5043. doi: 10.3390/cancers13205043.
For advanced breast cancer with lymph node involvement, adjuvant radiotherapy (RT) with regional nodal irradiation (RNI) has been indicated to reduce cancer recurrence and mortality. However, an extensive RT volume is associated with normal organ exposure, which increases the toxicity and affects patient outcomes. Modern arc RT techniques can improve normal organ sparing compared with conventional techniques. The aim of this study was to explore the optimal technique for left-breast RT with RNI.
We retrospectively reviewed patients receiving RT with RNI for left-breast cancer. We used modern arc RT techniques with either volumetric-modulated arc therapy (VMAT) or helical tomotherapy (HT) with a novel block technique, and compared differences in dosimetry parameters between the two groups. Subgroup analysis of RNI with or without internal mammary node (IMN) volume was also performed.
A total of 108 eligible patients were enrolled between 2017 and 2020, of whom 70 received VMAT and 38 received HT. The median RT dose was 55 Gy. No significant differences were found regarding the surgery, RT dose, number of fractions, target volume, and RNI volume between the VMAT and HT groups. VMAT reduced the heart mean dose more than HT (3.82 vs. 5.13 Gy, < 0.001), as well as the cardiac parameters of V5-V20, whole-lung mean dose, lung parameters of V5-V20, and contralateral-breast and esophagus mean dose. In the subgroup analysis of RNI with IMNs, the advantage of VMAT persisted in protecting the heart, lung, contralateral breast, and esophagus. HT was beneficial for lowering the thyroid mean dose. For RNI without IMN, VMAT improved the low-dose exposure of the heart and lung, but HT was similar to VMAT in terms of heart, whole-lung, and contralateral-breast mean dose.
For patients with left-breast cancer receiving adjuvant RT with RNI, VMAT reduced the exposure dose to the heart, lung, contralateral breast, and esophagus compared with HT. VMAT was superior to HT in terms of normal organ sparing in the patients who underwent RNI with IMN irradiation. Considering the reduction in normal organ exposure and potential toxicity, VMAT is the optimal technique for patients receiving RNI when deep inspiration breath-hold is not available.
对于有淋巴结转移的晚期乳腺癌，辅助放疗（RT）联合区域淋巴结照射（RNI）已被证实可降低癌症复发率和死亡率。然而，较大的放疗体积会导致正常器官受照，这会增加毒性并影响患者预后。与传统技术相比，现代弧形放疗技术可更好地保护正常器官。本研究旨在探索左乳放疗联合RNI的最佳技术。
我们回顾性分析了接受左乳腺癌放疗联合RNI的患者。我们使用了现代弧形放疗技术，包括容积调强弧形放疗（VMAT）或螺旋断层放疗（HT）以及一种新型挡块技术，并比较了两组剂量学参数的差异。还对包含或不包含内乳淋巴结（IMN）体积的RNI进行了亚组分析。
2017年至2020年期间共纳入108例符合条件的患者，其中70例接受VMAT，38例接受HT。中位放疗剂量为55 Gy。VMAT组和HT组在手术方式、放疗剂量、分次次数、靶体积和RNI体积方面未发现显著差异。VMAT降低心脏平均剂量的效果优于HT（3.82 Gy对5.13 Gy，<0.001），同时也降低了V5 - V20的心脏参数、全肺平均剂量、V5 - V20的肺参数以及对侧乳腺和食管平均剂量。在包含IMN的RNI亚组分析中，VMAT在保护心脏、肺、对侧乳腺和食管方面的优势依然存在。HT有利于降低甲状腺平均剂量。对于不包含IMN的RNI，VMAT改善了心脏和肺的低剂量受照情况，但在心脏、全肺和对侧乳腺平均剂量方面，HT与VMAT相似。
对于接受辅助放疗联合RNI的左乳腺癌患者，与HT相比，VMAT降低了心脏、肺、对侧乳腺和食管的受照剂量。在接受包含IMN照射的RNI患者中，VMAT在保护正常器官方面优于HT。考虑到正常器官受照剂量的降低和潜在毒性，当无法进行深吸气屏气时，VMAT是接受RNI患者的最佳技术。
