Simultaneous integrated boost with spot scanning proton beam irradiation for meningiomas
Carola Luetgendorf-Caucig,
Austria
PO-1122
Abstract
Simultaneous integrated boost with spot scanning proton beam irradiation for meningiomas
Authors: Carola Luetgendorf-Caucig1, Eugen Hug2, Maciej Pelak1, Birgit Flechl1, Piero Fossati1, Marta Momot3, Antonio Carlino3, Christoph Lukas Hajdusich1, Petra Georg4
1MedAustron, Radiation Oncology, Wiener Neustadt, Austria; 2MedAustron, Radiation Oncology, Wiener Neustast, Austria; 3MedAustron, Medical Physics, Wiener Neustadt, Austria; 4MedAsutron, Radiation Oncology, Wiener Neustadt, Austria
Show Affiliations
Hide Affiliations
Purpose or Objective
Meningiomas are the most common CNS tumors and the majority is regarded as benign. However, a subset of patients presents with complex tumors involving several anatomic compartments of the skull base - eluding concepts of gross total resection. Proton therapy (PT) is applied as definitive treatment for primary or recurrent disease or postoperatively following subtotal resection.
We report on the first 100 adult patients treated with PT at MedAustron Ion Therapy Center
Material and Methods
All patients were enrolled in the prospective registry trial. Target volume definition was based on CT, MR and DOTA-PET/CT. CTV1 included tumour (GTVMR/PET), and 5mm margin along the meninges, CTV2 was limited to GTVMR/PET. PT PBS treatment plans were generated by applying the SFIB-optimisation method and utilizing 2-4 beams per plan with a beam spacing of >30°. Prescribed doses to PTV1 were 50.49Gy_RBE at 1.87Gy_RBE/fr and 54.0Gy_RBE at 2.0Gy_RBE/fr to PTV2 in overall 27 fractions. Follow up status was assessed with MRI at 6, 12 months post treatment and annually thereafter, side effects were assessed using CTCAE v4.0. and quality of life (QoL) using EORTC-C30 and BN20 questionnaires. The scores entered by the patients were added and normalized to 0-100 scale according to previously described protocols.
Results
Between 08/2017 and 04/2021, 100 patients were treated, 22% (n=22) male and 78% (n=78) female patients. Median age at therapy was 54a (25a-82a). In 57% (n=57) PT was the definitive treatment (no surgery or surgery >12 mo prior to PT). 43% (n=43) underwent at least one surgery (range 1-3) prior to PT, with median time between surgery and start of PT of 6mo (3mo-11mo). 89% (n=89) meningiomas were located in the skull base with involvement of multiple anatomic compartments. The median GTV was 24cc (1cc-226cc) and the median CTV 41cc (2cc-352cc), respectively.
At median follow-up of 36.5 month (12.7mo- 54.1mo), 1 local in-field failures were observed resulting in local control of 97.8% (95%CI: 91.5-99.5)
At 3 years. No > grade 2 acute toxicity was observed. During follow-up two grade 3 toxicities occurred: One patient developed symptomatic radiation induced brain lesion (RIBL) which resolved within 12 month; one patient was hospitalized for new onset of epilepsy without corresponding radiographic findings. The general QoL including the global health status and all functioning domains was not compromised following proton radiotherapy.
Conclusion
First clinical data demonstrate that PT based on SFIB is a safe and efficient treatment of anatomically complex, low grade meningiomas. Acute and late toxicity incidences in our series were low with excellent, prospectively assessed preservation of QoL.