Retrospective Analysis of the Factors Affecting Recurrence, Survival, and the Effect of Hippocampus Radiotherapy Doses on Neurocognitive Functions in Patients treated with the Diagnosis of Glioblastoma Multiforme

Effects of Radiotherapy in Patients with Glioblastoma Multiforme

Abstract

Objective: In this study, it is aimed to evaluate radiotherapy doses, radiotherapy’s effects on neurocognitive functions, and possible factors that may affect recurrence or death in patients with glioblastoma multiforme (GBM).

Methods: The data of 21 patients with GBM are analyzed retrospectively. Radiotherapy treatment plans and doses, and hippocampus ipsilateral and contralateral doses were recorded. The Mini-Mental State Examination (MMSE) is used to assess neurocognitive functions. The time of recurrence and death, if any, of the patients were recorded. The factors such as gender, age, patient performance status, tumor size, tumor localization, type of surgery, and time between surgery and radiotherapy (RT) were analyzed to determine any effect on the risk of recurrence or death.

Results: The median planning target volume (PTV) dose was 59.86 Gray (Gy). The maximum ipsilateral hippocampus dose was 51.85 Gy, and the maximum contralateral hippocampus dose was 46.25 Gy. With the MMSE, 3 of 4 patients had cognitive impairment. At the end of follow-up, 16 patients had recurrence and died. The median disease-free survival was 10 months (95% CI: 5.7- 14.2), the median overall survival was 24 months (95% CI: 16.0- 31.9). Only poor performance status was found to increase the risk of recurrence (HR: 4.31, 95% CI:1.26-14.70, p=0.02). 

Conclusion: Since hippocampus shielding was not performed, our hippocampus doses were high. Hippocampal-sparing radiotherapy is essential for preserving neurocognitive functions. The increased risk of recurrence in patients with poor performance status is possibly related to treatment dose reduction, delay, or discontinuation.