Diagnostic Imaging and Radiotherapy, CODTIS, Faculty of Health Sciences, National University of Malaysia, Jalan Raja Muda Aziz, 50300, Kuala Lumpur, Malaysia.
Functional Image Processing Laboratory, Department of Radiology, Universiti Kebangsaan Malaysia Medical Centre, Cheras, 56000, Kuala Lumpur, Malaysia.
Support Care Cancer. 2021 Jun;29(6):3035-3047. doi: 10.1007/s00520-020-05808-z. Epub 2020 Oct 11.
Proton therapy (PT), frequently utilised to treat paediatric brain tumour (PBT) patients, eliminates exit dose and minimises dose to healthy tissues that theoretically can mitigate treatment-related effects including cognitive deficits. As clinical outcome data are emerging, we aimed to systematically review current evidence of cognitive changes following PT of PBT.
We searched PubMed and Scopus electronic databases to identify eligible reports on cognitive changes following PT of PBT according to PRISMA guidelines. Reports were extracted for information on demographics and cognitive outcomes. Then, they were systematically reviewed based on three themes: (1) comparison with photon therapy, (2) comparison with baseline cognitive measures, to population normative mean or radiotherapy-naïve PBT patients and (3) effects of dose distribution to cognition.
Thirteen reports (median size (range): 70 (12-144)) were included. Four reports compared the cognitive outcome between PBT patients treated with proton to photon therapy and nine compared with baseline/normative mean/radiotherapy naïve from which two reported the effects of dose distribution. Reports found significantly poorer cognitive outcome among patients treated with photon therapy compared with proton therapy especially in general cognition and working memory. Craniospinal irradiation (CSI) was consistently associated with poorer cognitive outcome while focal therapy was associated with minor cognitive change/difference. In limited reports available, higher doses to the hippocampus and temporal lobes were implicated to larger cognitive change.
Available evidence suggests that PT causes less cognitive deficits compared with photon therapy. Children who underwent focal therapy with proton were consistently shown to have low risk of cognitive deficit suggesting the need for future studies to separate them from CSI. Evidence on the effect of dose distribution to cognition in PT is yet to mature.
质子治疗（PT）常用于治疗儿科脑肿瘤（PBT）患者，可消除出口剂量并最大限度地减少对健康组织的剂量，理论上可以减轻治疗相关影响，包括认知缺陷。随着临床结果数据的出现，我们旨在系统地综述目前关于 PBT 质子治疗后认知变化的证据。
我们按照 PRISMA 指南，在 PubMed 和 Scopus 电子数据库中搜索关于 PBT 质子治疗后认知变化的合格报告。提取报告信息，包括人口统计学和认知结果。然后，我们根据三个主题进行系统综述：（1）与光子治疗的比较，（2）与基线认知测量的比较，与人群正常值或未经放疗的 PBT 患者比较，（3）剂量分布对认知的影响。
共纳入 13 项报告（中位数大小（范围）：70（12-144））。四项报告比较了接受质子和光子治疗的 PBT 患者的认知结果，九项报告与基线/正常值/未经放疗的患者比较，其中两项报告了剂量分布的影响。报告发现，接受光子治疗的患者认知结果明显较差，尤其是在总体认知和工作记忆方面。全脑全脊髓照射（CSI）与认知结果较差相关，而局灶性治疗与较小的认知变化/差异相关。在有限的可用报告中，海马体和颞叶的较高剂量与较大的认知变化相关。
现有证据表明，与光子治疗相比，PT 引起的认知缺陷较少。接受质子局灶性治疗的儿童一直显示出认知缺陷的低风险，这表明需要未来的研究将他们与 CSI 分开。关于 PT 中剂量分布对认知的影响的证据尚未成熟。
