Department of Radiation Oncology and Cancer Imaging.
Department of Radiotherapy.
Ann Oncol. 2012 May;23(5):1259-1266. doi: 10.1093/annonc/mdr439. Epub 2011 Oct 6.
Chemotherapy plus radiotherapy is the standard of care for patients with limited stage Hodgkin lymphoma (HL). Radiotherapy is evolving from involved field radiotherapy (IFRT) to involved node radiotherapy (INRT) to decrease radiotherapy-related morbidity. In the absence of long-term toxicity data, dose-volume metrics of organs at risk (OAR) provide a surrogate measure of toxicity risk.
Ten female patients with stage I-IIA supradiaphragmatic HL were randomly selected. All patients had pre-chemotherapy computerised tomography (CT) and CT-positron emission tomography staging. Using CT planning, three radiotherapy plans were produced per patient: (i) IFRT, (ii) INRT using parallel-opposed beams and (iii) INRT using volumetric modulated arc therapy (VMAT). Radiotherapy dose was 30.6 Gy in 1.8 Gy fractions. OAR evaluated were lungs, breasts, thyroid, heart and coronary arteries.
Compared with IFRT, INRT significantly reduced mean doses to lungs (P < 0.01), breasts (P < 0.01), thyroid (P < 0.01) and heart (P < 0.01), on Wilcoxon testing. Compared with conventional INRT, VMAT improved dose conformality but increased low-dose radiation exposure to lungs and breasts. VMAT reduced the heart volume receiving 30 Gy (V30) by 85%.
Reduction from IFRT to INRT decreased the volumes of lungs, breasts and thyroid receiving high-dose radiation, suggesting the potential to reduce long-term second malignancy risks. VMAT may be useful for patients with pre-existing heart disease by minimising further cardiac toxicity risks.
化疗加放疗是局限期霍奇金淋巴瘤（HL）患者的标准治疗方法。为了降低放疗相关的发病率，放疗正在从受累野放疗（IFRT）向累及淋巴结放疗（INRT）发展。在缺乏长期毒性数据的情况下，危险器官（OAR）的剂量-体积指标提供了一种毒性风险的替代衡量标准。
随机选择了 10 名患有 I-IIA 期膈上 HL 的女性患者。所有患者均在化疗前进行了计算机断层扫描（CT）和 CT 正电子发射断层扫描分期。使用 CT 计划，每位患者产生了三种放疗计划：（i）IFRT，（ii）使用平行对置束的 INRT，（iii）使用容积调制弧形治疗（VMAT）的 INRT。放疗剂量为 30.6Gy，分为 1.8Gy 的分次。评估的 OAR 包括肺、乳房、甲状腺、心脏和冠状动脉。
与 IFRT 相比，INRT 显著降低了肺（P < 0.01）、乳房（P < 0.01）、甲状腺（P < 0.01）和心脏（P < 0.01）的平均剂量，Wilcoxon 检验。与传统的 INRT 相比，VMAT 提高了剂量适形性，但增加了肺部和乳房的低剂量辐射暴露。VMAT 将接受 30Gy 照射的心脏体积（V30）减少了 85%。
从 IFRT 减少到 INRT 降低了肺、乳房和甲状腺接受高剂量辐射的体积，这表明有可能降低长期第二恶性肿瘤的风险。VMAT 通过最大限度地减少进一步的心脏毒性风险，可能对患有先前存在的心脏病的患者有用。
