Song Yuanfang, Yu Ting, Wang Wei, Li Jianbin, Sun Tao, Qiu Pengfei, Xu Min, Shao Qian
Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan.
Tianjin Medical University, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin.
Medicine (Baltimore). 2019 Oct;98(41):e17549. doi: 10.1097/MD.0000000000017549.
The study aimed to evaluate and compare the dosimetric parameters of incidental irradiation to internal mammary node (IMN) from inverse intensity-modulated radiotherapy (I-IMRT) and field-in-field IMRT (F-IMRT), and 3-dimensional conformal radiotherapy (3D-CRT) in patients after breast-conservation surgery (BCS).
Eighty-four patients with BCS were selected. The breast, tumor bed, and IMN, including intercostal spaces (ICS) 1 to 3, were contoured. Three plans were generated. The prescription doses for the breast and tumor bed were 50.4 Gy/28 F and 60.2 Gy/28 F, respectively. If there was no tumor bed boost, patient was treated with 50 Gy/25 F for the whole breast only. The IMN was not included in planning target volume.
The median mean dose (Dmean) of the IMNtotal (ICS 1-3) was 2740.2 cGy, 2973.9 cGy, and 2951.4 cGy for I-IMRT, F-IMRT, and 3D-CRT, respectively. Differences were not detected between any of the plans. After separating ICS 1 to 3 for further analysis, neither of the Dmean of ICS 1 to 2 was significantly different between the plans. However, for ICS 3, the median Dmean was highest for I-IMRT, and those for 3D-CRT and F-IMRT were not significantly different. After separating the 3 techniques for further analysis, the median Dmean was highest in ICS 3 and lowest in ICS 1 for all the 3 techniques.
All 3 techniques failed to attain an adequate dose to cure subclinical disease, and there were no significant differences among the 3 techniques. It is risky to avoid IMN irradiation (IMNI) using any of the 3 techniques during whole-breast radiotherapy in women with indications for elective IMNI. However, in era of systematic therapy, whether the incidental dose could meet clinical acquirements needs further follow-up.
本研究旨在评估和比较保乳手术（BCS）后患者接受逆向调强放疗（I-IMRT）、野中野调强放疗（F-IMRT）和三维适形放疗（3D-CRT）时，内乳淋巴结（IMN）的偶然照射剂量学参数。
选取84例BCS患者。勾勒出乳房、瘤床和IMN，包括第1至3肋间间隙（ICS）。生成三个计划。乳房和瘤床的处方剂量分别为50.4 Gy/28次分割和60.2 Gy/28次分割。如果没有瘤床加量，患者仅接受全乳50 Gy/25次分割的治疗。IMN不包括在计划靶体积内。
I-IMRT、F-IMRT和3D-CRT的IMNtotal（ICS 1-3）的中位平均剂量（Dmean）分别为2740.2 cGy、2973.9 cGy和2951.4 cGy。各计划之间未检测到差异。将ICS 1至3分开进行进一步分析后，各计划之间ICS 1至2的Dmean均无显著差异。然而，对于ICS 3，I-IMRT的中位Dmean最高，3D-CRT和F-IMRT的中位Dmean无显著差异。将这三种技术分开进行进一步分析后，所有三种技术的中位Dmean在ICS 3中最高，在ICS 1中最低。
所有三种技术均未能达到治愈亚临床疾病的足够剂量，且三种技术之间无显著差异。对于有选择性IMN照射指征的女性，在全乳放疗期间使用这三种技术中的任何一种避免IMN照射（IMNI）都存在风险。然而，在系统治疗时代，偶然剂量是否能满足临床要求需要进一步随访。
