乳腺癌术后胸壁和锁骨上区整体调强剂量学探讨

Irradiation of the chest wall and regional nodes as an integrated volume with IMRT for breast cancer after mastectomy:from dosimetry to clinical observation

目的探讨乳腺癌改良根治术后胸壁靶区和锁骨上靶区整体调强计划的剂量学特点,并观察照射后的急性不良反应。方法 146例乳腺癌改良根治术后患者进行治疗计划设计,43例整体调强计划选择3个针对胸壁靶区、2个针对锁骨上靶区、1个针对总的靶区共6个照射野进行整体逆向调强计划,103例患者计划选择胸壁靶区2个切线野的三维适形,再衔接锁骨上靶区单野6MVX线和9MeV电子线混合照射的适形接野计划。计划处方剂量均为25次50Gy,90%的靶区达到处方剂量;并分别对胸壁靶区、锁骨上靶区、正常器官的剂量学特点进行比较。结果胸壁靶区整体调强计划比适形接野计划降低了最大剂量,提高了最小剂量,有更好的靶区适形性和均匀性。锁骨上靶区整体调强计划最小剂量、平均剂量、95%处方剂量包含的靶区体积均有明显的提高,靶区适形性和均匀性有显著的改善。危及器官整体调强计划同侧肺V30、心脏V10、V30、Dmean均低于适形接野计划,而V5、V10、心脏V5高于后者,同侧肺V20、Dmean、对侧肺Dmean、对侧乳腺Dmean无统计学差异,患者发生Ⅱ级以上放射性皮炎38%,且两组间无统计学意义,未发生放射性肺炎。结论在不增加危及器官受量的前提下,应用整体调强技术能明显改善锁骨上靶区的剂量,提高胸壁靶区和锁骨上靶区的剂量适形性和均匀性,值得推广应用。

Objective To discuss dosimetric characteristics of integrated volume for chest wall target and supraclavicular target with IMRT for breast cancer after mastectomy, and observe a- cute side - effects following irradiation. Methods It was plan for breast cancer after mastectomy of 146cases, the plan for integrated volume with IMRT for breast cancer in 43 cases choice3 fields for chest wall target area and 2 fields for supraclavicular target area and lfield for the total target area, the general plan in 103 cases was 3D - CRT for chest wall target joining plan of mixed irradiation by 6 MV X- ray and 9 MeV electronic line for supraclavicular target, prescription dose was 50 Gy/25 times, to meet the requirements of 90 % prescription dose for target area; and dosimetry characteris- tics on the chest wall target and supraclavicular target area and normal organ are compared. Results The plan of integrated volume with IMRT for breast cancer for the chest wall target area com- pared with general plan reduces the maximum dose and enhance the minimum dose and a better tar- get conformal and uniformity. The plan of integrated volume with IMRT for breast cancer for Supr- aclavicular target area compared with general plan, the minimum dose and the average dose of pre- scription dose and 95 % contains the target volume, and conformal and uniformity for the target re- gion was increased obviously. The plan of integrated volume with IMRT for breast cancer for the normal organ compared with general plan, the V30 and V10 and V30 and Dmean d the ipsi｜ateral lung and heart were lowed, while the V5 and V10 of the ipsilateral lung and heart were increased, it were no statistical difference of V20 of the ipsilateral lung and Dm^n of the eontralateral lung and Dmean of the contralateral breast, 〉/grade 2 radiational dermatitis was identified in 38 % patients, no patient developed radiation pneumonitis. Conclusion The plan for integrated volume with [MRT for breast cancer can improve the dose of supraclavicular target significantly by the quantity under the premise for organ at risk and improve conformal and uniformity of the dose for chest wall target area and supracfavicular target volume.