Department of Radiation Oncology, Brigham and Women's Hospital, Dana-Farber Cancer Institute, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts.
Department of Radiation and Molecular Radiation Sciences, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, Maryland.
Int J Radiat Oncol Biol Phys. 2019 Dec 1;105(5):1034-1042. doi: 10.1016/j.ijrobp.2019.08.039. Epub 2019 Aug 28.
Brainstem necrosis is a rare, but dreaded complication of radiation therapy; however, data on the incidence of brainstem injury for tumors involving the posterior fossa in photon-treated patient cohorts are still needed.
Clinical characteristics and dosimetric parameters were recorded for 107 pediatric patients who received photon radiation for posterior fossa tumors without brainstem involvement from 2000 to 2016. Patients were excluded if they received a prescription dose <50.4 Gy, a brainstem maximum dose <50.4 Gy, or had fewer than 2 magnetic resonance imaging scans within 18 months after radiation. Post-radiation therapy magnetic resonance imaging findings were recorded, and brainstem toxicity was graded using National Cancer Institute Common Terminology Criteria for Adverse Events, version 5.
The most common histologies were medulloblastoma (61.7%) and ependymoma (15.9%), and median age at diagnosis was 8.3 years (range, 0.8-20.7). Sixty-seven patients (62.6%) received craniospinal irradiation (median, 23.4 Gy; range, 18.0-39.6) as a component of their radiation therapy, and 39.3% and 40.2% of patients received an additional involved field or whole posterior fossa boost, respectively. Median prescribed dose was 55.8 Gy (range, 50.4-60.0). Median clinical and imaging follow-up were 4.7 years (range, 0.1-17.5) and 4.2 years (range, 0.1-17.3), respectively. No grade ≥2 toxicities were observed. The incidence of grade 1 brainstem necrosis was 1.9% (2 of 107). These patients were by definition asymptomatic and experienced resolution of imaging abnormality after 5.3 months and 2.1 years, respectively.
Risk of brainstem necrosis was minimal in this multi-institutional study of pediatric patients treated with photon radiation therapy for tumors involving the posterior fossa with no cases of symptomatic brainstem injury, suggesting that brainstem injury risk is minimal in patients treated with photon therapy.
脑干坏死是放疗的一种罕见但可怕的并发症；然而，仍需要关于光子治疗患者队列中涉及后颅窝的肿瘤的脑干损伤发生率的数据。
对 2000 年至 2016 年间接受光子放疗的 107 例无脑干受累的后颅窝肿瘤患儿的临床特征和剂量学参数进行了记录。如果患者接受的处方剂量<50.4Gy、脑干最大剂量<50.4Gy 或在放疗后 18 个月内进行的磁共振成像扫描少于 2 次，则将其排除在外。记录放疗后磁共振成像结果，并使用国家癌症研究所不良事件常用术语标准，版本 5 对脑干毒性进行分级。
最常见的组织学类型是髓母细胞瘤（61.7%）和室管膜瘤（15.9%），诊断时的中位年龄为 8.3 岁（范围，0.8-20.7）。67 例（62.6%）患者接受了颅脊髓照射（中位剂量 23.4Gy；范围，18.0-39.6）作为放疗的一部分，39.3%和 40.2%的患者分别接受了额外的累及野或全后颅窝推量。中位处方剂量为 55.8Gy（范围，50.4-60.0）。中位临床和影像学随访时间分别为 4.7 年（范围，0.1-17.5）和 4.2 年（范围，0.1-17.3）。未观察到≥2 级毒性。1.9%（2/107）的患者出现 1 级脑干坏死。这些患者根据定义无症状，分别在 5.3 个月和 2.1 年后影像学异常得到缓解。
在这项涉及光子放疗治疗后颅窝肿瘤的多机构研究中，脑干坏死的风险极小，没有出现症状性脑干损伤的病例，这表明光子治疗的患者脑干损伤风险极小。
