Department of Radiation Oncology, Keck School of Medicine of the University of Southern California, Los Angeles, California.
Children's Center for Cancer and Blood Diseases, Children's Hospital Los Angeles, Los Angeles, California.
Pediatr Blood Cancer. 2018 Jul;65(7):e27050. doi: 10.1002/pbc.27050. Epub 2018 Apr 6.
Craniospinal irradiation (CSI) is an important part of curative radiation therapy (RT) for many types of pediatric brain or solid tumors. After conventional CSI, long term survivors may experience sequelae due to unintended dose to normal tissue. Volumetric modulated arc therapy (VMAT) CSI reduces off-target doses at the cost of greater complexity and error risk, and we describe our initial experience in a group of pediatric patients with solid tumors presenting with disseminated or recurrent disease.
Pediatric patients with brain tumors were identified at Children's Hospital Los Angeles from 2013 to 2015. Clinical characteristics, acute toxicity, and radiotherapy data were abstracted from their medical records. We identified 19 patients who received VMAT CSI. Quality assurance was performed with a cylindrical detector array and ion chamber measurements at the arc junctions.
Patients had medulloblastoma or supratentorial primitive neuro-ectodermal tumor (n = 14, 11 high risk), germ cell tumors (two), relapsed neuroblastoma (two), and atypical teratoid/rhabdoid tumor (one). The most common acute toxicity was hematologic, including leukopenia (11% grade [Gr] 2, 26% Gr 3, and 63% Gr 4), anemia (89% Gr 2), and thrombocytopenia (16% Gr 1-2, 26% Gr 3, and 37% Gr 4). Despite leukopenia, we encountered only two Gr 3 infections (urinary tract and lung). The majority required blood products (89% red blood cells and 68% platelets). Weight loss was also common (47% Gr 1 and 26% Gr 2).
VMAT CSI, along with chemotherapy and anesthesia, is feasible with supportive care. Daily image-guided RT improves accuracy and reduces the risk of spinal cord overdose without increasing treatment time. Further research is needed to determine whether reducing doses to organs, such as thyroid, heart, or hippocampus, offsets the risk of increased volume of low-dose irradiation.
颅脊髓照射（CSI）是许多类型儿童脑或实体瘤的根治性放射治疗（RT）的重要组成部分。在常规 CSI 之后，长期存活者可能会因正常组织的意外剂量而出现后遗症。容积调强弧形治疗（VMAT）CSI 降低了靶外剂量，但代价是增加了复杂性和错误风险，我们描述了一组患有弥散性或复发性疾病的实体瘤儿童患者的初步经验。
2013 年至 2015 年，洛杉矶儿童医院对患有脑肿瘤的儿科患者进行了识别。从他们的病历中提取了临床特征、急性毒性和放射治疗数据。我们共识别出 19 名接受 VMAT CSI 的患者。使用圆柱形探测器阵列和弧形交界处的离子室测量进行了质量保证。
患者患有髓母细胞瘤或幕上原始神经外胚层肿瘤（n=14，11 例为高危）、生殖细胞瘤（2 例）、复发性神经母细胞瘤（2 例）和非典型畸胎瘤/横纹肌样瘤（1 例）。最常见的急性毒性是血液学毒性，包括白细胞减少（11%为 2 级，26%为 3 级，63%为 4 级）、贫血（89%）和血小板减少（16%为 1-2 级，26%为 3 级，37%为 4 级）。尽管有白细胞减少症，但我们只遇到了两例 3 级感染（尿路感染和肺部感染）。大多数患者需要输血制品（89%的红细胞和 68%的血小板）。体重减轻也很常见（47%为 1 级，26%为 2 级）。
VMAT CSI 联合化疗和麻醉，在支持治疗下是可行的。每日图像引导 RT 提高了准确性，降低了脊髓超量照射的风险，而不增加治疗时间。需要进一步研究以确定是否降低甲状腺、心脏或海马等器官的剂量是否可以抵消增加低剂量照射体积的风险。
