Institute of Biostructures and Bioimaging, National Council of Research, Napoli, Italy.
Radiat Oncol. 2013 Jan 30;8:22. doi: 10.1186/1748-717X-8-22.
Purpose of this study is to explore the trade-offs between radio-induced toxicities and second malignant neoplasm (SMN) induction risk of different emerging radiotherapy techniques for Hodgkin's lymphoma (HL) through a comprehensive dosimetric analysis on a representative clinical model.
Three different planning target volume (PTVi) scenarios of a female patient with supradiaphragmatic HL were used as models for the purpose of this study. Five treatment radiation techniques were simulated: an anterior-posterior parallel-opposed (AP-PA), a forward intensity modulated (FIMRT), an inverse intensity modulated (IMRT), a Tomotherapy (TOMO), a proton (PRO) technique. A radiation dose of 30 Gy or CGE was prescribed. Dose-volume histograms of PTVs and organs-at-risk (OARs) were calculated and related to available dose-volume constraints. SMN risk for breasts, thyroid, and lungs was estimated through the Organ Equivalent Dose model considering cell repopulation and inhomogeneous organ doses.
With similar level of PTVi coverage, IMRT, TOMO and PRO plans generally reduced the OARs' dose and accordingly the related radio-induced toxicities. However, only TOMO and PRO plans were compliant with all constraints in all scenarios. For the IMRT and TOMO plans an increased risk of development of breast, and lung SMN compared with AP-PA and FIMRT techniques was estimated. Only PRO plans seemed to reduce the risk of predicted SMN compared with AP-PA technique.
Our model-based study supports the use of advanced RT techniques to successfully spare OARs and to reduce the risk of radio-induced toxicities in HL patients. However, the estimated increase of SMNs' risk inherent to TOMO and IMRT techniques should be carefully considered in the evaluation of a risk-adapted therapeutic strategy.
本研究旨在通过对代表性临床模型的全面剂量学分析，探讨不同新兴放射治疗技术在霍奇金淋巴瘤（HL）中放射性毒性与第二恶性肿瘤（SMN）诱导风险之间的权衡。
本研究采用一名女性膈上 HL 患者的三个不同计划靶区（PTVi）场景作为模型。模拟了五种治疗放射技术：前后平行对置（AP-PA）、前向调强（FIMRT）、逆向调强（IMRT）、托姆治疗（TOMO）和质子（PRO）技术。规定放射剂量为 30Gy 或 CGE。计算了 PTV 和危及器官（OAR）的剂量体积直方图，并与可用的剂量体积限制相关联。通过考虑细胞再增殖和不均匀器官剂量的器官等效剂量模型，估计了乳房、甲状腺和肺部的 SMN 风险。
在 PTVi 覆盖水平相似的情况下，IMRT、TOMO 和 PRO 计划通常会降低 OAR 剂量，从而降低相关放射性毒性。然而，只有 TOMO 和 PRO 计划在所有场景中都符合所有约束条件。对于 IMRT 和 TOMO 计划，与 AP-PA 和 FIMRT 技术相比，估计了乳房和肺部 SMN 发展的风险增加。仅 PRO 计划似乎降低了与 AP-PA 技术相比预测的 SMN 风险。
我们的基于模型的研究支持使用先进的 RT 技术成功保护 OAR 并降低 HL 患者放射性毒性的风险。然而，TOMO 和 IMRT 技术固有的 SMN 风险增加应在风险适应治疗策略的评估中仔细考虑。
