Epidemiology, clinical features and prognosis for medulloblastoma relapse depending on the molecular subgroups in children and adolescents

The 2016 World Health Organization classification of central nervous system tumors for the first time provided the division of medulloblastoma (MB) into molecular subgroups which determine treatment response, the likelihood of relapse, the outcome of the disease and prognosis. The course of the disease and prognosis are also expected to be influenced by a number of genetic factors, such as the amplification of the MYC family genes and mutations in the TP53 gene. MB relapse has a heterogeneous clinical course, poor prognosis and continues to be a therapeutic challenge. We conducted retrospective and prospective analyses of the data from the group of 50 pediatric and adolescent patients with MB relapse. A morphology review and the determination of molecular subgroups were performed at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology (Moscow, Russia) from January 2014 to December 2023. The aim of the study is to identify the specific differences in MB relapse in 50 pediatric and adolescent patients, depending on their molecular subgroup. An anatomical site of relapse, time to relapse, postrelapse survival and the effectiveness of various relapse treatment regimens were studied. The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology.