I am going to assume that this child was treated with high dose chemotherapy and no cranio-spinal irradiation prior to this progression since this is the most often used approach albeit not the only one. As all practicing pediatric Neuro-oncologists are aware, this age group is one of the most ...

I fully agree with Dr. @Upadhyaya. Please read the excellent paper from Erker et al., PMID 36548930. It contains a wealth of information (real life) that can help with the decision, including subgrouping.