Nagar Himanshu, Zhou Lili, Biritz Bertrand, Sison Cristina, Chang Jenghwa, Smith Michael, Nori Dattatreyudu, Chao K S Clifford, Hayes Mary Katherine
Department of Radiation Oncology, Weill Medical College of Cornell University, New York, NY.
Department of Radiation Oncology, Weill Medical College of Cornell University, New York, NY.
Clin Breast Cancer. 2014 Apr;14(2):109-13. doi: 10.1016/j.clbc.2013.10.004. Epub 2013 Oct 27.
Recent data are changing axillary management in patients with 1 to 2 positive sentinel nodes. The proposed omission of completion axillary node dissection calls into question the need for axillary nodal irradiation. This study evaluates the difference in dose to the lung and heart and risk of radiation pneumonitis (RP) for patients treated with standard tangent fields (STF) compared with modified high tangent fields (MHTF).
Plans of 30 patients treated with STF were evaluated. A second plan (MHTF) was developed to include axillary levels I (Ax1) and II (Ax2). Ax1 and Ax2 volumes were contoured based on the RTOG (Radiation Therapy Oncology Group) Atlas guidelines. Dose-volume histograms of the 2 plans were used to compare doses received by Ax1, Ax2, lung, and heart volumes. The risk of RP was calculated using normal tissue complication probability (NTCP) modeling.
The D95 (dose to 95% of volume) received by Ax1 and Ax2 volumes increased from 16.38 Gy and 5.71 Gy for STF to 49.38 Gy and 48.08 Gy for MHTF, respectively. Mean lung dose increased from 5.40 Gy for STF to 9.47 Gy for MHTF. Mean ipsilateral lung V5, V10, and V20 values increased from 19%, 14%, and 10%, respectively, for STF, to 32%, 24%, and 18%, respectively, for MHTF. Mean heart dose increased from 1.98 Gy for STF to 3.93 Gy for MHTF. Mean heart V25 and V30 values increased from 2% and 1%, respectively, for STF, to 4% and 3%, respectively, for MHTF. NTCP for RP increased from near 0% for STF to 1% for MHTF.
Modified high tangent fields are necessary for definitive coverage of Ax1 and Ax2. This technique increases mean ipsilateral lung and heart doses as well as the V5, V10, and V20 of ipsilateral lung and the V25 and V30 of the heart. Risk of RP remains low by use of MHTF.
最新数据正在改变1 - 2枚前哨淋巴结阳性患者的腋窝处理方式。提议省略腋窝淋巴结清扫术引发了对腋窝淋巴结放疗必要性的质疑。本研究评估了与改良高切线野（MHTF）相比，采用标准切线野（STF）治疗的患者肺部和心脏所接受的剂量差异以及放射性肺炎（RP）的风险。
评估了30例采用STF治疗患者的计划。制定了第二个计划（MHTF），包括腋窝Ⅰ（Ax1）和Ⅱ（Ax2）水平。Ax1和Ax2体积根据美国放射肿瘤学会（RTOG）图谱指南进行勾画。使用两个计划的剂量体积直方图来比较Ax1、Ax2、肺部和心脏体积所接受的剂量。使用正常组织并发症概率（NTCP）模型计算RP风险。
Ax1和Ax2体积所接受的D95（95%体积的剂量）分别从STF的16.38 Gy和5.71 Gy增加到MHTF的49.38 Gy和48.08 Gy。平均肺部剂量从STF的5.40 Gy增加到MHTF的9.47 Gy。同侧肺部的平均V5、V10和V20值分别从STF的19%、14%和10%增加到MHTF的32%、24%和18%。平均心脏剂量从STF的1.98 Gy增加到MHTF的3.93 Gy。心脏的平均V25和V30值分别从STF的2%和1%增加到MHTF的4%和3%。RP的NTCP从STF的接近0%增加到MHTF的1%。
改良高切线野对于Ax1和Ax2的确定性覆盖是必要的。该技术增加了同侧肺部和心脏的平均剂量以及同侧肺部的V5、V10和V20以及心脏的V25和V30。使用MHTF时RP风险仍然较低。
