Abstract Whole brain radiotherapy (WBRT) is the standard radiotherapy regimen of preventive radiation for patients diagnosed with brain metastases and non-small cell lung cancer, which can improve intracranial control and prolong overall survival. However, neurocognitive functions (NCF) decline due to impaired hippocampal might occur thereafter. Recent studies have shown that hippocampal sparing WBRT (HS-WBRT) is capable of protecting neurocognitive function and improving quality of life (QOL). In this review, the authors described the methods and significance of hippocampal sparing, summarized the research progress on clinical trials related to HS-WBRT in combination with the development of radiotherapy technology and experimental drugs, and discussed the existing controversies and problems, aiming to provide reference for clinical work.
[1] Brown PD, Ahluwalia MS, Khan OH, et al.Whole-brain radiotherapy for brain metastases: evolution or revolution?[J]. J Clin Oncol, 2018,36(5):483-491. DOI: 10.1200/JCO.2017.75.9589.
[2] Goetz P, Ebinu JO, Roberge D, et al.Current standards in the management of cerebral metastases[J]. Int J Surg Oncol, 2012,2012:493426. DOI: 10.1155/2012/493426.
[3] Liu L, Zhao T, Zhong Q, et al.The role of prophylactic cranial irradiation in patients with non-small cell lung cancer: an updated systematic review and meta-analysis[J]. Front Oncol, 2020,10:11. DOI: 10.3389/fonc.2020.00011.
[4] Sun A, Bae K, Gore EM, et al.Phase III trial of prophylactic cranial irradiation compared with observation in patients with locally advanced non-small-cell lung cancer: neurocognitive and quality-of-life analysis[J]. J Clin Oncol, 2011,29(3):279-286. DOI: 10.1200/JCO.2010.29.6053.
[5] Brown PD, Jaeckle K, Ballman KV, et al.Effect of radiosurgery alone vs radiosurgery with whole brain radiation therapy on cognitive function in patients with 1 to 3 brain metastases: a randomized clinical trial[J]. JAMA, 2016,316(4):401-409. DOI: 10.1001/jama.2016.9839.
[6] Laack NN, Brown PD.Cognitive sequelae of brain radiation in adults[J]. Semin Oncol, 2004,31(5):702-713. DOI: 10.1053/j.seminoncol.2004.07.013.
[7] Chang EL, Wefel JS, Hess KR, et al.Neurocognition in patients with brain metastases treated with radiosurgery or radiosurgery plus whole-brain irradiation: a randomised controlled trial[J]. Lancet Oncol, 2009,10(11):1037-1044. DOI: 10.1016/S1470-2045(09)70263-3.
[8] Li J, Bentzen SM, Li J, et al.Relationship between neurocognitive function and quality of life after whole-brain radiotherapy in patients with brain metastasis[J]. Int J Radiat Oncol Biol Phys, 2008,71(1):64-70. DOI: 10.1016/j.ijrobp.2007.09.059.
[9] Opitz B.Memory function and the hippocampus[J]. Front Neurol Neurosci, 2014,34:51-59. DOI: 10.1159/000356422.
[10] Scoville WB, Milner B.Loss of recent memory after bilateral hippocampal lesions[J]. J Neurol Neurosurg Psychiatry, 1957,20(1):11-21. DOI: 10.1136/jnnp.20.1.11.
[11] Abayomi OK.Pathogenesis of irradiation-induced cognitive dysfunction[J]. Acta Oncol, 1996,35(6):659-663. DOI: 10.3109/02841869609083995.
[12] Kalm M, Karlsson N, Nilsson MK, et al.Loss of hippocampal neurogenesis, increased novelty-induced activity, decreased home cage activity, and impaired reversal learning one year after irradiation of the young mouse brain[J]. Exp Neurol, 2013,247:402-409. DOI: 10.1016/j.expneurol.2013.01.006.
[13] Ingraham JP, Forbes ME, Riddle DR, et al.Aging reduces hypoxia-induced microvascular growth in the rodent hippocampus[J]. J Gerontol A Biol Sci Med Sci, 2008,63(1):12-20. DOI: 10.1093/gerona/63.1.12.
[14] Farhood B, Goradel NH, Mortezaee K, et al.Intercellular communications-redox interactions in radiation toxicity; potential targets for radiation mitigation[J]. J Cell Commun Signal, 2019,13(1):3-16. DOI: 10.1007/s12079-018-0473-3.
[15] Chakraborti A, Allen A, Allen B, et al.Cranial irradiation alters dendritic spine density and morphology in the hippocampus[J]. PLoS One, 2012,7(7):e40844. DOI: 10.1371/journal.pone.0040844.
[16] Gondi V, Tome WA, Marsh J, et al.Estimated risk of perihippocampal disease progression after hippocampal avoidance during whole-brain radiotherapy: safety profile for RTOG 0933[J]. Radiother Oncol, 2010,95(3):327-331. DOI: 10.1016/j.radonc.2010.02.030.
[17] Gondi V, Tomé WA, Mehta MP.Why avoid the hippocampus? A comprehensive review[J]. Radiother Oncol, 2010,97(3):370-376. DOI: 10.1016/j.radonc.2010.09.013.
[18] Gondi V, Pugh SL, Tome WA, et al.Preservation of memory with conformal avoidance of the hippocampal neural stem-cell compartment during whole-brain radiotherapy for brain metastases (RTOG 0933): a phase II multi-institutional trial[J]. J Clin Oncol, 2014,32(34):3810-3816. DOI: 10.1200/JCO.2014.57.2909.
[19] 高瀚, 翟振宇, 贾鹏飞, 等. VMAT与IMRT在脑转移瘤全脑照射保护海马计划比较[J]. 中华放射肿瘤学杂志, 2018, 27(11): 989-993. DOI: 10.3760/cma.j.issn.1004-4221.2018.11.008.
Gao H, Zhai ZY, Jia PF, et al. Comparison of dose distribution between VMAT and IMRT in patients with brain metastases during hippocampus-sparing whole brain radiotherapy[J]. Chinese Journal of Radiation Oncology, 2018, 27(11): 989-993. DOI: 10.3760/cma.j.issn.1004-4221.2018.11.008.
[20] Gondi V, Tolakanahalli R, Mehta MP, et al.Hippocampal-sparing whole-brain radiotherapy: a "how-to" technique using helical tomotherapy and linear accelerator-based intensity-modulated radiotherapy[J]. Int J Radiat Oncol Biol Phys, 2010,78(4):1244-1252. DOI: 10.1016/j.ijrobp.2010.01.039.
[21] Gondi V, Cui Y, Mehta MP, et al.Real-time pretreatment review limits unacceptable deviations on a cooperative group radiation therapy technique trial: quality assurance results of RTOG 0933[J]. Int J Radiat Oncol Biol Phys, 2015,91(3):564-570. DOI: 10.1016/j.ijrobp.2014.10.054.
[22] Pan K, Zhao L, Gu S, et al.Deep learning-based automatic delineation of the hippocampus by MRI: geometric and dosimetric evaluation[J]. Radiat Oncol, 2021,16(1):12. DOI: 10.1186/s13014-020-01724-y.
[23] Dye NB, Gondi V, Mehta MP.Strategies for preservation of memory function in patients with brain metastases[J]. Chin Clin Oncol, 2015,4(2):24. DOI: 10.3978/j.issn.2304-3865.2015.05.05.
[24] 申静, 杨延灵, 胜照杰, 等. 海马保护技术在脑转移瘤全脑放疗患者中的应用效果[J].临床研究, 2021,29(8):8-10.
Shen J, Yang YL, Sheng ZJ, et al.Effect of hippocampal protection technique in patients with brain metastases treated with whole-brain radiotherapy[J]. Clinical Research, 2021,29(8):8-10.
[25] Ciesielska N, Sokołowski R, Mazur E, et al.Is the montreal cognitive assessment (MoCA) test better suited than the mini-mental state examination (MMSE) in mild cognitive impairment (MCI) detection among people aged over 60? Meta-analysis[J]. Psychiatr Pol, 2016,50(5):1039-1052. DOI: 10.12740/PP/45368.
[26] Rodríguez de Dios N, Couñago F, López JL, et al. Treatment design and rationale for a randomized trial of prophylactic cranial irradiation with or without hippocampal avoidance for SCLC: PREMER trial on behalf of the oncologic group for the study of lung cancer/Spanish radiation oncology group-radiation oncology clinical research group[J]. Clin Lung Cancer, 2018,19(5):e693-e697. DOI: 10.1016/j.cllc.2018.05.003.
[27] Sánchez-Benavides G, Peña-Casanova J, Casals-Coll M, et al.Cognitive and neuroimaging profiles in mild cognitive impairment and Alzheimer's disease: data from the Spanish Multicenter Normative Studies (NEURONORMA Project)[J]. J Alzheimers Dis, 2014,41(3):887-901. DOI: 10.3233/JAD-132186.
[28] Ajithkumar T, Price S, Horan G, et al.Prevention of radiotherapy-induced neurocognitive dysfunction in survivors of paediatric brain tumours: the potential role of modern imaging and radiotherapy techniques[J]. Lancet Oncol, 2017,18(2):e91-e100. DOI: 10.1016/S1470-2045(17)30030-X.
[29] 周陈丹, 张爱军. 儿童ALL患者治疗后的中枢神经系统结构和认知功能改变的Meta分析[D]. 济南: 山东大学, 2020.
Zhou CD, Zhang AJ.Changes in the structure and cognitive function of central nervous system in childhood acute lymphoblastic leukemia survivors: a meta-analysis[D]. Ji'nan: Shandong University, 2020.
[30] Li J, Bentzen SM, Renschler M, et al.Regression after whole-brain radiation therapy for brain metastases correlates with survival and improved neurocognitive function[J]. J Clin Oncol, 2007,25(10):1260-1266. DOI: 10.1200/JCO.2006.09.2536.
[31] Dimitropoulos C, Hillas G, Nikolakopoulou S, et al.Prophylactic cranial irradiation in non-small cell lung cancer patients: who might be the candidates?[J]. Cancer Manag Res, 2011,3:287-294. DOI: 10.2147/CMR.S22717.
[32] Harth S, Abo-Madyan Y, Zheng L, et al.Estimation of intracranial failure risk following hippocampal-sparing whole brain radiotherapy[J]. Radiother Oncol, 2013,109(1):152-158. DOI: 10.1016/j.radonc.2013.09.009.
[33] Rodríguez de Dios N, Couñago F, Murcia-Mejía M, et al. Randomized phase III trial of prophylactic cranial irradiation with or without hippocampal avoidance for small-cell lung cancer (PREMER): a GICOR-GOECP-SEOR study[J]. J Clin Oncol, 2021,39(28):3118-3127. DOI: 10.1200/JCO.21.00639.
[34] Cho Y, Lee J, Lee IJ, et al.Intracranial failure after hippocampal-avoidance prophylactic cranial irradiation in limited-stage small-cell lung cancer patients[J]. Sci Rep, 2021,11(1):7435. DOI: 10.1038/s41598-021-86851-6.
[35] Duman JG, Dinh J, Zhou W, et al.Memantine prevents acute radiation-induced toxicities at hippocampal excitatory synapses[J]. Neuro Oncol, 2018,20(5):655-665. DOI: 10.1093/neuonc/nox203.
[36] Brown PD, Gondi V, Pugh S, et al.Hippocampal avoidance during whole-brain radiotherapy plus memantine for patients with brain metastases: phase III trial NRG oncology CC001[J]. J Clin Oncol, 2020,38(10):1019-1029. DOI: 10.1200/JCO.19.02767.
[37] Rapp SR, Case LD, Peiffer A, et al.Donepezil for irradiated brain tumor survivors: a phase III randomized placebo-controlled clinical trial[J]. J Clin Oncol, 2015,33(15):1653-1659. DOI: 10.1200/JCO.2014.58.4508.
[38] 任陈, 李旋子, 杜莎莎. 维生素E通过抑制铁坏死减少放射性神经损伤[J].南方医科大学学报,2020,40(8):1097-1102. DOI: 10.12122/j.issn.1673-4254.2020.08.05.
Ren C, Li XZ, Du SS.Vitamin E reduces radiation injury of hippocampal neurons in mice by inhibiting ferroptosis[J]. Journal of Southern Medical University, 2020,40(8):1097-1102. DOI: 10.12122/j.issn.1673-4254.2020.08.05.
[39] Zhang J, Zhang Y, Xu M, et al.Inhibition of the CDK5/caspase-3 pathway by p5-TAT protects hippocampal neurogenesis and alleviates radiation-induced cognitive dysfunction[J]. Neuroscience, 2021,463:204-215. DOI: 10.1016/j.neuroscience.2021.03.034.