ESTRO 2024 - Abstract Book

S792

Clinical - CNS

ESTRO 2024

Acute radio-induced Adverse Events (RIAEs) were reported in 68% of patients (n=119), with most experiencing cutaneous/mucosal toxicity such as alopecia, radiation dermatitis, oral mucositis, and soft tissue oedema. Only 2 cases of Grade 3 acute RIAEs were reported, with no PT interruptions due to acute toxicity or complications. At least one long-term, any-grade PT-related toxicity was documented in 80 patients (46%). Among G2-G3 toxicities, 17 patients experienced pituitary toxicity requiring hormone replacement therapy. Two patients reported G2 optic nerve toxicity with a moderate decrease in visual acuity, while 2 other patients experienced G3 optic nerve toxicity with a marked decrease in visual acuity. Grade 2 cranial nerve disorders were reported in 17 patients, primarily suffering from trigeminal neuropathy with moderate symptoms requiring medication.

Any grade of RN related to PT was documented in 28 patients, but steroids or other medications were necessary for symptom management in only 12 patients (G2-G3 CTCAE). No Grade 4 or 5 adverse events were documented.

Patients with RN showed MRI-detected intensity modification within a median value of 40 months after PT. The univariable analysis revealed a statistically significant association between treatment dose and RNFS (p= 0.006). We also explored the relationship between RN and CTV, this relationship did not reach statistical significance (p=0.06). Patients with a CTV volume <31 cc had a 5-year RNFS of 95% whereas patients with a CTV volume greater than 31cc had a 5-year RNFS of 86%.

Conclusion:

PT is an advantageous treatment option for intracranial extra-axial tumors such as meningioma and hemangiopericytoma. PT seems to be an effective and safe treatment and it has demonstrated benefits in terms of OS, LC, and DRFS. Moreover, PT exhibits a low incidence of acute and late RIAEs. The treatment dose administered played a significant role in RN during the follow up period. These results prompt to explore the role of PT in prospective trials with longer follow-up.

Keywords: proton, radionecrosis, intracranial tumors

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Digital Poster

Treatment Dilemma of H3K27M Mutant Midline Glioma in Adults

Esengul Kocak Uzel 1 , Melisa Bagci Kilic 2

1 Health Sciences University Bakirkoy Dr. Sadi Konuk Training and Research Hospital, Radiation Oncology, Istanbul, Turkey. 2 Marmara University School of Medicine, Radiation Oncology, Istanbul, Turkey

Purpose/Objective:

Treatment of H3K27M mutant midline gliomas is a significant challenge. Therefore, our aim was to assess the efficacy of radiotherapy for these patients.