Lin Jang-Chun, Tsai Jo-Ting, Chang Chih-Chieh, Jen Yee-Min, Li Ming-Hsien, Liu Wei-Hsiu
From the Department of Radiation Oncology, Shuang Ho Hospital, Taipei Medical University (J-CL, J-TT, C-CC, Y-MJ, M-HL); Department of Radiation Oncology, Tri-Service General Hospital, National Defense, Medical Center (J-CL); Graduate Institute of Medical Sciences (W-HL); and Department of Neurological Surgery, Tri-Service General Hospital and National Defense Medical Center, Taipei, Taiwan (W-HL).
Medicine (Baltimore). 2015 May;94(17):e750. doi: 10.1097/MD.0000000000000750.
The aim of this study was to compare treatment plans of volumetric modulated arc therapy (VMAT) with intensity-modulated radiotherapy (IMRT) for all esophageal cancer (EC) tumor locations.This retrospective study from July 2009 to June 2014 included 20 patients with EC who received definitive concurrent chemoradiotherapy with radiation doses >50.4 Gy. Version 9.2 of Pinnacle with SmartArc was used for treatment planning. Dosimetric quality was evaluated based on doses to several organs at risk, including the spinal cord, heart, and lung, over the same coverage of gross tumor volume.In upper thoracic EC, the IMRT treatment plan had a lower lung mean dose (P = 0.0126) and lung V5 (P = 0.0037) compared with VMAT; both techniques had similar coverage of the planning target volumes (PTVs) (P = 0.3575). In middle thoracic EC, a lower lung mean dose (P = 0.0010) and V5 (P = 0.0145), but higher lung V20 (P = 0.0034), spinal cord Dmax (P = 0.0262), and heart mean dose (P = 0.0054), were observed for IMRT compared with VMAT; IMRT provided better PTV coverage. Patients with lower thoracic ECs had a lower lung mean dose (P = 0.0469) and V5 (P = 0.0039), but higher spinal cord Dmax (P = 0.0301) and heart mean dose (P = 0.0020), with IMRT compared with VMAT. PTV coverage was similar (P = 0.0858) for the 2 techniques.IMRT provided a lower mean dose and lung V5 in upper thoracic EC compared with VMAT, but exhibited different advantages and disadvantages in patients with middle or lower thoracic ECs. Thus, choosing different techniques for different EC locations is warranted.
本研究的目的是比较容积调强弧形放疗（VMAT）与调强放疗（IMRT）针对所有食管癌（EC）肿瘤位置的治疗计划。这项回顾性研究涵盖了2009年7月至2014年6月期间接受确定性同步放化疗且放射剂量>50.4 Gy的20例EC患者。使用带有SmartArc的Pinnacle 9.2版本进行治疗计划。基于在相同大体肿瘤体积覆盖范围内对包括脊髓、心脏和肺在内的多个危及器官的剂量来评估剂量学质量。在上段胸段EC中，与VMAT相比，IMRT治疗计划的肺平均剂量更低（P = 0.0126），肺V5更低（P = 0.0037）；两种技术对计划靶体积（PTV）的覆盖相似（P = 0.3575）。在中段胸段EC中，与VMAT相比，IMRT的肺平均剂量更低（P = 0.0010），V5更低（P = 0.0145），但肺V20更高（P = 0.0034），脊髓Dmax更高（P = 0.0262），心脏平均剂量更高（P = 0.0054）；IMRT提供了更好的PTV覆盖。下段胸段EC患者与VMAT相比，IMRT的肺平均剂量更低（P = 0.0469），V5更低（P = 0.0039），但脊髓Dmax更高（P = 0.0301），心脏平均剂量更高（P = 0.0020）。两种技术的PTV覆盖相似（P = 0.0858）。与VMAT相比，IMRT在上段胸段EC中提供了更低的平均剂量和肺V5，但在中段或下段胸段EC患者中表现出不同的优缺点。因此，针对不同的EC位置选择不同的技术是有必要的。
