AP-HP. Department of Radiation Oncology and Henri Mondor Breast Center, Créteil, France.
University of Paris-Est (UPEC), Créteil, France.
Br J Radiol. 2020 Jun;93(1110):20190351. doi: 10.1259/bjr.20190351. Epub 2020 Apr 1.
Our study aimed to compare regional node coverage and doses to the organ at risk (OAR) using conventional technique (CT) "AMAROS" (AT) intensity-modulated radiation therapy (IMRT) techniques in patients receiving regional nodal irradiation (RNI) for breast cancer (BC).
We included 30 consecutive patients with BC who received RNI including axillary nodes. Two independent and blinded dosimetric RNI plans were generated for all patients. For target volume coverage, we analyzed the V95%, the D95%, the mean and the minimal dose within the nodal station. For hotspots within nodal target volume, we used the V105%, the V108% and the maximal doses. For OAR, lung V20, mean lung and heart doses, the maximal dose to the brachial plexus and the axillary-lateral thoracic vessel junction region were compared between the three techniques.
Target volume coverage and hotspots: Mean V95% in stations I, II, III and IV were 35.8% and 75% respectively with CV, 22.59 and 59.9% respectively with AT technique and 45.58 and 99.6% respectively with IMRT with statistically significant differences ( < 0.001). Mean V105% (cc) in axillary and supraclavicular stations were 21.3 and 6.4 respectively with CV, 1.2 and 0.02 respectively with AT technique and 0.5 and 0.4 respectively with IMRT with statistically significant differences ( < 0.001)..OARs: The mean ipsilateral lung V20 was 16.9%, 16.4 and 13.3% with CT, AT and IMRT respectively. The mean heart dose (Gy) was 0.3, 0.2 and 0.2 with CT, AT and IMRT respectively. The maximal dose to the plexus brachial (Gy) was 50.3, 46.3 and 47.3 with CT, AT and IMRT respectively. The maximal dose to the axillary-lateral thoracic vessel junction (Gy) was 52.3, 47.3 and 47.6 with CT, AT and IMRT respectively. The differences were statistically significant for all OAR ( < 0.001).
AT is a valuable technique for RNI including axilla in patients with limited sentinel lymph node biopsy involvement without additional axillary lymph node dissection since it decreases hotspots in the target volume and lowers the radiation exposure of the OAR. For more advanced tumors or patients who did not respond to primary systemic therapy, CT or IMRT should be considered because of their better coverage of the potentially residual nodal disease. IMRT combines several advantages of offering high conformal plans, limited hotspots and protection of main OAR. The clinical impact of these dosimetric differences need to be addressed.
This study is to our knowledge the first to compare conventional three-dimensional and IMRT techniques for regional nodal irradiation for each nodal station in breast cancer in a context of increasing utilization of .
本研究旨在比较接受乳腺癌区域淋巴结照射（RNI）的患者使用常规技术（CT）“AMAROS”（AT）调强放疗（IMRT）技术与 AT 技术的区域淋巴结覆盖和危及器官（OAR）剂量。
我们纳入了 30 例接受包括腋窝淋巴结在内的 RNI 的连续乳腺癌患者。为所有患者生成了两个独立且盲目的 RNI 剂量学计划。对于靶区覆盖率，我们分析了淋巴结站的 V95%、D95%、平均剂量和最小剂量。对于淋巴结靶区内的热点，我们使用了 V105%、V108%和最大剂量。对于 OAR，肺 V20、平均肺和心脏剂量、臂丛神经和腋窝-侧胸血管交界处区域的最大剂量，在三种技术之间进行了比较。
靶区覆盖率和热点：I、II、III 和 IV 站的平均 V95%分别为 35.8%和 75%，变异系数分别为 22.59%和 59.9%；AT 技术分别为 45.58%和 99.6%；IMRT 分别为 45.58%和 99.6%，差异具有统计学意义（<0.001）。腋窝和锁骨上淋巴结的平均 V105%（cc）分别为 21.3 和 6.4，CV 分别为 1.2 和 0.02，AT 技术分别为 0.5 和 0.4，IMRT 分别为 0.5 和 0.4，差异具有统计学意义（<0.001）。OAR：CT、AT 和 IMRT 的同侧肺 V20 平均值分别为 16.9%、16.4%和 13.3%。心脏平均剂量（Gy）分别为 0.3、0.2 和 0.2 Gy。臂丛神经最大剂量（Gy）分别为 50.3、46.3 和 47.3 Gy。腋窝-侧胸血管交界处最大剂量（Gy）分别为 52.3、47.3 和 47.6 Gy。所有 OAR 的差异均具有统计学意义（<0.001）。
AT 是一种有价值的技术，适用于 Sentinel 淋巴结活检受累有限的患者进行包括腋窝在内的 RNI，而无需进行额外的腋窝淋巴结清扫，因为它降低了靶区内的热点并降低了 OAR 的辐射暴露。对于更晚期的肿瘤或对初始全身治疗无反应的患者，由于其更好地覆盖潜在的残留淋巴结疾病，应考虑使用 CT 或 IMRT。IMRT 结合了提供高适形计划、限制热点和保护主要 OAR 的优势。需要解决这些剂量学差异的临床影响。
本研究首次比较了常规三维和 IMRT 技术在乳腺癌中每个淋巴结站的区域淋巴结照射，这是在越来越多的使用背景下进行的。
