Department of Oncology, Sahlgrenska University Hospital, Gothenburg, Sweden (M.B.); Centre for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden (M.B.); Radiation Medicine Research Center, Department of Radiation Oncology, Rigshospitalet, Copenhagen, Denmark (N.P.B., P.M.R., A.K.-B., C.H., I.R.V., S.M.B.); Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark (N.P.B., P.M.R.); Department of Clinical Physiology and Nuclear Medicine, Centre of Diagnostic Investigations, Copenhagen, Denmark (A.K.-B.); Department of Pediatric Oncology, the Queen Silvia Children's Hospital, University of Gothenburg, Gothenburg, Sweden (B.L.); Department of Human Oncology, University of Wisconsin Medical School, Madison, Wisconsin (S.M.B.); Department of Radiation Oncology, Sahlgrenska University Hospital, Gothenburg, Sweden (T.B.-E.).
Neuro Oncol. 2014 Apr;16(4):594-602. doi: 10.1093/neuonc/not225. Epub 2013 Dec 9.
We investigated how varying the treatment margin and applying hippocampal sparing and proton therapy impact the risk of neurocognitive impairment in pediatric medulloblastoma patients compared with current standard 3D conformal radiotherapy.
We included 17 pediatric medulloblastoma patients to represent the variability in tumor location relative to the hippocampal region. Treatment plans were generated using 3D conformal radiotherapy, hippocampal sparing intensity-modulated radiotherapy, and spot-scanned proton therapy, using 3 different treatment margins for the conformal tumor boost. Neurocognitive impairment risk was estimated based on dose-response models from pediatric CNS malignancy survivors and compared among different margins and treatment techniques.
Mean hippocampal dose and corresponding risk of cognitive impairment were decreased with decreasing treatment margins (P < .05). The largest risk reduction, however, was seen when applying hippocampal sparing proton therapy-the estimated risk of impaired task efficiency (95% confidence interval) was 92% (66%-98%), 81% (51%-95%), and 50% (30%-70%) for 3D conformal radiotherapy, intensity-modulated radiotherapy, and proton therapy, respectively, for the smallest boost margin and 98% (78%-100%), 90% (60%-98%), and 70% (39%-90%) if boosting the whole posterior fossa. Also, the distance between the closest point of the planning target volume and the center of the hippocampus can be used to predict mean hippocampal dose for a given treatment technique.
We estimate a considerable clinical benefit of hippocampal sparing radiotherapy. In choosing treatment margins, the tradeoff between margin size and risk of neurocognitive impairment quantified here should be considered.
我们研究了在与当前标准的 3D 适形放疗相比，改变治疗边缘并应用海马保护和质子治疗对小儿髓母细胞瘤患者神经认知障碍风险的影响。
我们纳入了 17 名小儿髓母细胞瘤患者，以代表肿瘤相对于海马区的位置变化。使用 3D 适形放疗、海马保护调强放疗和点扫描质子治疗，对 3 种不同的适形肿瘤增强治疗边缘生成治疗计划。根据小儿中枢神经系统恶性肿瘤幸存者的剂量反应模型估计神经认知障碍风险，并在不同的边缘和治疗技术之间进行比较。
随着治疗边缘的减小，平均海马剂量和相应的认知障碍风险降低（P <.05）。然而，当应用海马保护质子治疗时，风险降低最大——对于最小的增强边缘，估计任务效率受损的风险（95%置信区间）分别为 3D 适形放疗（66%-98%）、调强放疗（51%-95%）和质子治疗（30%-70%），分别为 3D 适形放疗、调强放疗和质子治疗；如果对整个后颅窝进行增强，分别为 98%（78%-100%）、90%（60%-98%）和 70%（39%-90%）。此外，计划靶区的最近点和海马中心之间的距离可用于预测给定治疗技术的平均海马剂量。
我们估计海马保护放疗具有相当大的临床益处。在选择治疗边缘时，应考虑这里量化的边缘大小和神经认知障碍风险之间的权衡。
