ESTRO 2024 - Abstract Book

S831

Clinical - CNS

ESTRO 2024

Brain regional progression at MRI_1 (MRI_1_Prog) occurred in 149/685 treatment courses (21.8%). Patients harboring a MRI_1_Prog had a significantly shorter overall survival than other patients (median OS: 194 days vs 482 days respectively, p < 0.0001). Among all clinical and dosimetric features, treatment of all brain metastases and histology of the primary tumour were significant predictors of MRI_1_Prog. In case of MRI_1_Prog, nor radiotherapy (RT) nor chemotherapy (CT) alone lead to significantly increased OS when compared to follow-up only. However, patients treated with both RT and CT achieved a significantly longer OS.

Conclusion:

This study highlights the impact of regional progression at MRI_1 on overall survival, showing the need for robust biomarkers of early brain relapse as well as the need of a specific management of such patients. In patients presenting with an early relapse, association of RT and CT achieved the highest OS results.

Keywords: Brain metastasis, Stereotactic radiotherapy

1159

Digital Poster

Hypofractionation versus conventional fractionation in real-world patients with glioblastoma.

Mário Esteves Leal 1 , Sofia Ramos 1 , Sara Simões 1 , Marina Amorim 1 , José Miguel Rocha 2 , Adelina Costa 3 , Carlos Fardilha 3 , Maria Rodrigues 1 , Cármen Calçada 3 , João Gagean 3 , Paulo Costa 3 1 Braga Hospital, Radiotherapy, Braga, Portugal. 2 Braga Hospital, Oncology, Braga, Portugal. 3 CUF Institute, Radiotherapy, Porto, Portugal

Purpose/Objective:

Glioblastoma is the most common primary brain tumor in adults. It is associated with poor prognosis. The standard treatment is maximal resection followed by concurrent radiotherapy and chemotherapy with temozolamide (TMZ). This study establishes a comparison in prognostic value and toxicity between glioblastoma patients treated with hypofractionation (HF) and those with conventional fractionation (CF) schemes.

Material/Methods:

All patients with histologic diagnosis of glioblastoma treated at our institution with radiotherapy between January 2019 and October 2023 were included. Hypofractionation was comprised of short-course radiotherapy, 40.5 Gy in 15 fractions, and conventional fractionation was considered 60Gy in 30 fractions. TMZ was the chemotherapy regimen in all patients. The variables studied were: gender, age, ECOG (Eastern Cooperative Oncology Group) score, interval between surgery and radiotherapy, surgical approach (biopsy or resection), imagiologic residue evaluation (Gross total resection GTR or Subtotal Resection STR), genetic variants, overall survival, progression-free survival, CTCAE (Common Terminology Criteria for Adverse Events) version 5.0 toxicity grade during treatment, corticosteroid