Assistance Publique Hopitaux de Marseille, France.
Institut Saint Joseph, Marseille, France.
Int J Radiat Oncol Biol Phys. 2018 Mar 15;100(4):980-986. doi: 10.1016/j.ijrobp.2017.12.265. Epub 2017 Dec 21.
To identify the incidence of patients with perihippocampal metastases to assess the risk of brain relapse when sparing the hippocampal area. Medulloblastoma (MB) represents 20% of pediatric brain tumors. For high-risk MB patients, the 3- to 5-year event-free survival rate has recently improved from 50% to >76%. Many survivors, however, experience neurocognitive side effects. Several retrospective studies of patients receiving whole brain irradiation (WBI) have suggested a relationship between the radiation dose to the hippocampus and neurocognitive decline. The hippocampal avoidance-WBI (HA-WBI) approach could partially reduce neurocognitive impairment in children treated for high-risk MB.
From 2008 to 2011, 51 patients with high-risk MB were treated according to the French trial primitive neuroectodermal tumor HR+5. Hippocampal contouring was manually generated on 3-dimensional magnetic resonance images according to the Radiation Therapy Oncology Group 0933 atlas. The distribution of metastases was assessed relative to the hippocampus: 0 to 5 mm for the first perihippocampal area and 5 to 15 mm for the rest of the perihippocampal area.
The median patient age was 8.79 years (33% female). After a follow-up of 2.4 years, 43 patients were alive; 28 had had brain metastasis at diagnosis and 2 at relapse, with 16% in the first perihippocampal area and 43% in the rest of the perihippocampal area. Of the 18 patients without brain metastases at diagnosis, including M1 patients, none developed secondary lesions within the first or the rest of the perihippocampal area, after receiving 36 Gy. No clinical or biological factor was significantly associated with the development of perihippocampal metastases.
Our results suggest the HA-WBI strategy should be evaluated for the subgroup of high-risk MB patients without metastatic disease.
确定海马旁转移患者的发病率，以评估在保留海马区时脑部复发的风险。髓母细胞瘤（MB）占儿童脑肿瘤的 20%。对于高危 MB 患者，最近 3 至 5 年无事件生存率已从 50%提高到>76%。然而，许多幸存者经历神经认知方面的副作用。几项接受全脑照射（WBI）的患者回顾性研究表明，海马剂量与神经认知下降之间存在关系。海马回避-WBI（HA-WBI）方法可部分减少高危 MB 患儿的神经认知损伤。
2008 年至 2011 年，51 例高危 MB 患者按照法国原始神经外胚层肿瘤 HR+5 试验进行治疗。根据放射治疗肿瘤学组 0933 图谱，在三维磁共振图像上手动生成海马轮廓。转移的分布相对于海马进行评估：第一海马旁区为 0 至 5 毫米，其余海马旁区为 5 至 15 毫米。
中位患者年龄为 8.79 岁（33%为女性）。随访 2.4 年后，43 例患者存活；28 例在诊断时发生脑转移，2 例在复发时发生脑转移，其中 16%位于第一海马旁区，43%位于其余海马旁区。在 18 例无诊断性脑转移的患者中，包括 M1 患者，在接受 36 Gy 照射后，均未在第一海马旁区或其余海马旁区出现继发性病变。没有临床或生物学因素与海马旁转移的发展有显著相关性。
我们的结果表明，HA-WBI 策略应在无转移性疾病的高危 MB 患者亚组中进行评估。
