ESTRO 2024 - Abstract Book

S956

Clinical - CNS

ESTRO 2024

Medical Sciences, Bydgoszcz, Poland. 20 Maria Skłodowska -Curie National Research Institute of Oncology, Gliwice Branch, IIIrd Radiotherapy and Chemotherapy Department, Gliwice, Poland

Purpose/Objective:

To investigate the long-term treatment results of adults with primary grade 3 (G3) ependymoma and to identify factors related to survival.

Material/Methods:

A retrospective analysis of all consecutive patients (pts) older than 18 years treated due to primary G3 intracranial ependymoma (EP) in 13 institutions was performed. Overall survival (OS) was calculated from the time of diagnosis until death. Progression-free survival (PFS) was calculated as the time from diagnosis until the development of local disease recurrence or metastases or death from any cause. Survival curves were plotted with the Kaplan-Meier method and compared using the log-rank test. The Cox proportional hazards model was used in univariate (UVA) and multivariate (MVA) analyses and backward stepwise model selection by AIC was performed.

Results:

The study group consisted of 84 pts with intracranial grade 3 ependymoma, with a median age of 42 years (18-77 range) and a small predominance of men (57% vs. 43%). Three of them had dissemination at the time of primary diagnosis. Supra- and infratentorial locations of the tumours were observed in 69% and 31% of pts, respectively. Performance status was evaluated as ECOG 0 or 1 in 75% and as ECOG 2 or 3 in 25% of pts. All pts had surgery as primary treatment with R0, R1 and R2 resection in 51%, 12% and 37% cases, respectively. Radiotherapy was applied with radical intention in 89% of cases and palliative in 11%. Four patients received chemotherapy in primary treatment. Among those who had radical radiotherapy, 52% had local irradiation and 48% craniospinal irradiation with local boost. The median total dose on tumour/tumour bed was 56 Gy. Median follow-up was 2.5 years. During that time, 48 pts died and 5- and 10-year OS was 45% and 31%, respectively. Analysis indicated that factors which had a statistically significant impact on OS in MVA were age (P<0.001, HR 1.045 [95%CI 1.023 – 1.068]), infratentorial tumour location (P=0.031, HR 0.391 [95%CI 0.167 – 0.919]), higher total dose (P=0.018, HR 0.963 [95%CI 0.933 – 0.994]) and treatment centre (P=0.020, HR 0.466 [95%CI 0.245 – 0.885]). Other independent factors included: local failure (P=0.121) and radical resection (P=0.08). Local failure and metastases were diagnosed in 39 and 19 cases, respectively. Five- and 10-year progression-free survival (PFS) was 36% and 25%, respectively. Analysis showed that factors which had a statistically significant impact on PFS in MVA were age (P=0.015, HR 1.021 [95%CI 1.004 – 1.038]), infratentorial tumour location (P<0.001, HR 0.225 [95%CI 0.100 – 0.505]), radical resection (P=0.001, HR 2.699 [95%CI 1.474 – 4.942]), higher total dose (P=0.002, HR 0.953 [95%CI 0.923 – 0.983]) and treatment centre (P=0.009, HR 0.462 [95%CI 0.259 – 0.821]). Irradiation on craniospinal axis did not benefit in better outcome in terms of OS, PFS, time to local recurrence or time to distant progression (p=0.22).

Conclusion: