Clinical outcome and quality of life of intracranial meningiomas treated with PBS Proton Therapy
MO-0553
Abstract
Clinical outcome and quality of life of intracranial meningiomas treated with PBS Proton Therapy
Authors: Reinhardt Krcek1,2, Dominic Leiser1, Alessandra Bolsi1, Damien C. Weber1,3,2
1Paul Scherrer Institute, ETH Domain, Center for Proton Therapy, Villigen, Switzerland; 2Inselspital, Bern University Hospital, University of Bern, Department of Radiation Oncology, Bern, Switzerland; 3University Hospital of Zürich, Department of Radiation Oncology, Zürich, Switzerland
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Purpose or Objective
Meningiomas are one of the most common primary brain tumors, with the majority being benign. The current standard therapy for symptomatic or growing lesions includes surgery and/or radiotherapy.
Proton beam therapy (PT) is characterized by its unique dose deposition pattern, with low entrance and no relevant exit dose beyond the target volume. Pencil beam scanning (PBS) PT improves conformality and Organs at risk sparing.
In this retrospective study, we assess the clinical outcome including quality of life (QoL) of patients with intracranial meningioma WHO Grade 1, 2 and 3 treated with PBS PT at the Center for Proton Therapy/Paul Scherrer Institute between 1997 and 2022.
Material and Methods
Two hundred patients with intracranial meningioma WHO Grade 1-3 (Median age 50.4 years, 72.5% female, 70% grade 1, 27.5% grade 2 and 2.5% grade 3) were analyzed.
Acute and late side effects were classified according to CTCAE version 5.0. Time to event data (Progression Free Survival (PFS) and Overall Survival (OS)) were calculated from the first day of PT using Kaplan-Meier estimates for the whole cohort, subgroups were compared by log-rank test and multivariable Cox regression (SPSS v28). QoL was assessed descriptively by the EORTC-QLQ-C30 and BN20 questionnaires.
Results
The median follow-up was 65 months (range 3.8-260.8 months). Five year local PFS was 94.2% for grade 1 and 66.5% for grade 2 or higher and the OS 95.7% and 81.8% for these two grade groups, respectively (both, p<0.001). Twenty local failures have been observed; of those 15 (75%) failures have been in-field, while 5 (25%) failures were marginal. Failures occurred significantly (p<0.008) more frequent in grade 2 or 3 meningiomas (grade 1: n=7, grade 2/3: n=13)), and when PT was initiated at the timepoint of progression or recurrence as opposed to upfront therapy (multivariable, p=0.006, univariable p=0.01).
We did not observed any high-grade late toxicity in a majority (n=176; 88%) of patients. Nevertheless, 24 grade 3 or higher toxicities were observed, mainly optic toxicity (grade 4 radiation-induced optic neuropathy or retinitis, n=11; grade 3 cataracts, n=4) and brain necrosis/stroke (grade 5, n=1; grade 3, n=4). No correlations of grade 3 toxicity or higher with histology and/or localization of the tumor (skull base vs. non-skull base) or sex, but a correlation with higher age (p=0.047, multivariable) was observed. QoL was assessed for 78 (39%) patients, of those 41 patients with a follow-up of at least 3 years. The result of the QoL analysis will be presented during ESTRO’s annual meeting
Conclusion
PBS Proton Therapy leads to a high local control in intracranial meningiomas with a low rate of high grade toxicity. Radiation-induced optic neuropathy was the most common high-grade late toxicity. As outcome was better when meningiomas were treated upfront and not in case of recurrence or tumor progression, early proton therapy should be considered for these meningioma patients.