Wang Lu, Li Chengqiang, Meng Xue, Li Chengming, Sun Xindong, Shang Dongping, Pang Linlin, Li Yixiao, Lu Jie, Yu Jinming
Department of Radiation Oncology, School of Medicine, Shandong University, Jinan, China.
Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China.
Front Oncol. 2019 Jul 25;9:674. doi: 10.3389/fonc.2019.00674. eCollection 2019.
To compare treatment plans of intensity modulated radiotherapy (IMRT), volumetric modulated arc radiotherapy (VMAT), and helical tomotherapy (HT) with simultaneous integrated boost (SIB) technique for esophageal cancer (EC) of different locations using dosimetry and radiobiology. Forty EC patients were planned for IMRT, VMAT, and HT plans, including 10 cases located in the cervix, upper, middle, and lower thorax, respectively. Dose-volume metrics, conformity index (CI), homogeneity index (HI), tumor control probability (TCP), and normal tissue complication probability (NTCP) were analyzed to evaluate treatment plans. HT showed significant improvement over IMRT and VMAT in terms of CI ( = 0.007), HI ( < 0.001), and TCP ( < 0.001) in cervical EC. IMRT yielded more superior CI, HI and TCP compared with VMAT and HT in upper and middle thoracic EC (all < 0.05). Additionally, V30 (27.72 ± 8.67%), mean dose (1801.47 ± 989.58cGy), and NTCP (Niemierko model: 0.44 ± 0.55%; Lyman-Kutcher-Burman model: 0.61 ± 0.59%) of heart in IMRT were sharply reduced than VMAT and HT in middle thoracic EC. For lower thoracic EC, the three techniques offered similar CI and HI (all > 0.05). But VMAT dramatically lowered liver V30 (9.97 ± 2.84%), and reduced NTCP of lungs (Niemierko model: 0.47 ± 0.48%; Lyman-Kutcher-Burman model: 1.41 ± 1.07%) and liver (Niemierko model: 0.10 ± 0.08%; Lyman-Kutcher-Burman model: 0.17 ± 0.17%). HT was a good option for cervical EC with complex target coverage but little lungs and heart involvement as it achieved superior dose conformity and uniformity. Due to potentially improving tumor control and reducing heart dose with acceptable lungs sparing, IMRT was a preferred choice for upper and middle thoracic EC with large lungs involvement. VMAT could ameliorate therapeutic ratio and lower lungs and liver toxicity, which was beneficial for lower thoracic EC with little thoracic involvement but being closer to heart and liver. Individually choosing optimal technique for EC in different location will be warranted.
采用剂量学和放射生物学方法,比较调强放射治疗(IMRT)、容积调强弧形放疗(VMAT)和螺旋断层放疗(HT)联合同步整合加量(SIB)技术治疗不同部位食管癌(EC)的治疗计划。对40例EC患者制定IMRT、VMAT和HT计划,其中分别有10例位于宫颈、胸上段、胸中段和胸下段。分析剂量体积指标、适形指数(CI)、均匀性指数(HI)、肿瘤控制概率(TCP)和正常组织并发症概率(NTCP)以评估治疗计划。在宫颈段EC中,HT在CI( = 0.007)、HI( < 0.001)和TCP( < 0.001)方面比IMRT和VMAT有显著改善。在胸上段和胸中段EC中,IMRT在CI、HI和TCP方面比VMAT和HT更优(均 < 0.05)。此外,在胸中段EC中,IMRT中心脏的V30(27.72 ± 8.67%)、平均剂量(1801.47 ± 989.58cGy)和NTCP(Niemierko模型:0.44 ± 0.55%;Lyman-Kutcher-Burman模型:0.61 ± 0.59%)比VMAT和HT大幅降低。对于胸下段EC,三种技术的CI和HI相似(均 > 0.05)。但VMAT显著降低了肝脏V30(9.97 ± 2.84%),并降低了肺(Niemierko模型:0.47 ± 0.48%;Lyman-Kutcher-Burman模型:1.41 ± 1.07%)和肝脏(Niemierko模型:0.10 ± 0.08%;Lyman-Kutcher-Burman模型:0.17 ± 0.17%)的NTCP。HT对于靶区覆盖复杂但肺和心脏受累少的宫颈段EC是一个好选择,因为它实现了更好的剂量适形性和均匀性。由于可能提高肿瘤控制并在可接受的肺受量情况下降低心脏剂量,IMRT是肺受累大的胸上段和胸中段EC的首选。VMAT可以改善治疗比并降低肺和肝脏毒性,这对于胸段受累少但更靠近心脏和肝脏的胸下段EC有益。有必要针对不同部位的EC分别选择最佳技术。