Abstract General Information

Title

SURVIVAL ANALYSIS AND PROGNOSTIC FACTORS IN POSTERIOR FOSSA EPENDYMOMAS IN CHILDREN AND TEENAGERS

Introduction, Objectives, Methods, Results, and Conclusion.

Introduction: Ependymoma is one of the most common neoplasms of the Central Nervous System to affect the pediatric age group. They occur in three topographies: supratentorial, posterior fossa and spinal cord, and the World Health Organization divides it in five subgroups: subependymomas, myxopapilar EPN, classical EPN, anaplastic EPN, and positive RELA gene fusion EPN. So far, the most effective treatment for them is maximum surgical resection followed by radiotherapy. However, some variants can make the tumor’s behavior unpredictable. Objective: We seek to analyze the overall and progression-free survival of patients under 18 years old diagnosed with posterior fossa ependymomas, observing prognostic factors, for e.g. the degree of surgical resection, involvement of rhombencephalon, molecular classification of the tumor and age group. Methods: We accessed medical records of patients within criteria treated at the institution since 2002 (n=55), and collected clinical data. Statistical analysis used Kaplan-Meyer survival curves and Logrank Mentel-cox or Logrank test for trend and Fisher's Exact tests. α was considered less than or equal to 0.05 for significance. Results: The morphology of brainstem involvement by the tumor showed significant difference in progression-free survival – the median survival (in months) for patients with dorsal only involvement was 28; for dorsolateral, 15; for total, 9,5 - p=0,0464. Despite that, overall survival (in months) for these groups showed no statistical difference – 44 for the 1st one, 74 for the 2nd group and 31,5 for 3rd involvement group - p = 0,2205. The subgroup analysis revealed significant contrast in the proportion of total resection in the group with dorsal involvement (73.08%) when compared to the group with total (0%) - p=0.0019. There was also a statistical difference for this proportion between the group with dorsolateral (60%) when compared to the group with total (0%) - p=0.0186. Conclusion: We confirmed previous findings, such as the impact of the extent of resection on overall and progression-free survival. Moreover, we concluded that the pattern of involvement of the brainstem by the tumor at diagnosis can bring important information regarding the prognosis of the patient in relation to disease-free survival and, likewise, the total involvement of the brainstem impairs total surgical resection of these tumors – unprecedented findings in the literature with potential value to clinical practice.

Keywords (separated by comma on a single line)

ependymoma,childhood,neurosurgeery