Wang Wei, Zhang Yingjie, Xu Min, Shao Qian, Sun Tao, Yu Ting, Liu Xijun, Li Jianbin
Department of Radiation Oncology, Shandong Cancer Hospital affiliated to Shandong University, Jinan, Shandong 250117, China,
Department of Medical Physics, Shandong Cancer Hospital affiliated with Shandong University, Jinan, Shandong 250117, China.
Cancer Manag Res. 2019 Jan 30;11:1097-1106. doi: 10.2147/CMAR.S191047. eCollection 2019.
To evaluate the incidental coverage dose to the internal mammary nodes (IMN) in patients treated with postmastectomy radiotherapy (PMRT) and its relationship with the treatment plan.
We retrospectively analyzed 138 patients undergoing PMRT and divided them into three groups: three-dimensional conformal radiotherapy (3D-CRT), field-in-field forward intensity-modulated radiotherapy (F-IMRT), and inverse intensity-modulated radiotherapy (I-IMRT). The IMN were contoured according to the Radiation Therapy Oncology Group consensus and not included in the planning target volume. We analyzed incidental IMN dose coverage and its relationship with the lung and heart.
The mean dose (Dmean) to the IMN was 32.85 Gy for all patients, and the dose delivered to the IMN showed no differences in 3D-CRT, F-IMRT, and I-IMRT (33.80, 29.65, and 32.95 Gy, respectively). In addition, 10.42%, 2.04%, and 9.76% of patients achieved ≥45 Gy with 3D-CRT, F-IMRT, and I-IMRT, respectively. No differences were evident among the three treatment plans regarding IMN dose in the first three intercostal spaces (ICS1-3). The Dmean, V20, V30, V40, and V50 of ICS2 and ICS3 were superior to those of ICS1 for all three plans. For 3D-CRT, a moderate positive correlation was evident between the Dmean to the IMN and the Dmean to the heart. For F-IMRT and I-IMRT, positive correlations were evident between the Dmean of the IMN and the Dmean and V20 of the lung.
The mean incidental dose to the IMN for IMRT (F-IMRT and I-IMRT) and 3D-CRT after modified radical mastectomy was insufficient to treat subclinical disease. A substantial dose was delivered to the IMN in some patients. Higher incidental doses to the IMN were associated with a higher heart mean dose for 3D-CRT and a higher dose to the lung for IMRT. Future prospective studies should further explore subgroups that do not require IMN irradiation.
评估接受乳房切除术后放疗（PMRT）的患者内乳淋巴结（IMN）的附带照射剂量及其与治疗计划的关系。
我们回顾性分析了138例接受PMRT的患者，并将他们分为三组：三维适形放疗（3D-CRT）、野中野正向调强放疗（F-IMRT）和逆向调强放疗（I-IMRT）。IMN根据放射治疗肿瘤学组的共识进行轮廓勾画，且不包括在计划靶体积内。我们分析了IMN的附带剂量覆盖情况及其与肺和心脏的关系。
所有患者IMN的平均剂量（Dmean）为32.85 Gy，在3D-CRT、F-IMRT和I-IMRT中给予IMN的剂量无差异（分别为33.80、29.65和32.95 Gy）。此外，3D-CRT、F-IMRT和I-IMRT分别有10.42%、2.04%和9.76%的患者达到≥45 Gy。在三个治疗计划中，前三肋间间隙（ICS1-3）的IMN剂量无明显差异。对于所有三个计划，ICS2和ICS3的Dmean、V20、V30、V40和V50均优于ICS1。对于3D-CRT，IMN的Dmean与心脏的Dmean之间存在中度正相关。对于F-IMRT和I-IMRT，IMN的Dmean与肺的Dmean和V20之间存在正相关。
改良根治性乳房切除术后IMRT（F-IMRT和I-IMRT）和3D-CRT对IMN的平均附带剂量不足以治疗亚临床疾病。一些患者的IMN接受了相当大的剂量。3D-CRT中IMN的附带剂量较高与心脏平均剂量较高相关，IMRT中与肺剂量较高相关。未来的前瞻性研究应进一步探索不需要IMN照射的亚组。
