ESTRO 2024 - Abstract Book

S912

Clinical - CNS

ESTRO 2024

2331

Mini-Oral

Adjuvant RT vs observation after neurosurgical resection in patients with grade 2 meningioma

Erica Maria Cuffini 1 , Andrea Bianconi 2 , Alessio Gastino 1 , Greta De Giorgi 1 , Giuliana Petruzzellis 1 , Fabio Cofano 2 , Giuseppe Palmieri 3 , Alessia Andrea Ricci 4 , Francesca Clot 1 , Beatrice Giuffrè 1 , Cristina Mantovani 1 , Luca Bertero 4 , Paola Cassoni 4 , Diego Garbossa 2 , Umberto Ricardi 1 , Mario Levis 1 1 University of Turin, Department of Oncology, Turin, Italy. 2 University of Turin, Department of Neurosciences, Neurosurgery, Turin, Italy. 3 Ospedale SS. Annunziata, Neurosurgery, Taranto, Italy. 4 University of Turin, Department of Medical Sciences, Pathology Unit, Turin, Italy

Purpose/Objective:

Meningiomas are the most common primary intracranial tumors. Neurosurgical resection has a pivotal role in the management of meningioma and it can be followed either by adjuvant radiotherapy (RT) or by observation depending on the extent of resection and the histological grading. The role of adjuvant RT for WHO grade 2 meningioma is still unclear, especially in patients who underwent gross total resection (GTR). 1,2,3,4 This study aims to assess the impact of adjuvant RT on local control (LC), intracranial progression free survival (iPFS) and overall survival (OS) in patients with resected grade 2 meningioma.

Material/Methods:

We retrospectively collected a consecutive series of patients with histologically proven diagnosis of WHO grade 2 meningioma, who underwent GTR or subtotal resection (STR) at our Hospital between 2010 and 2020. Our population was then stratified in two cohorts: patients receiving adjuvant RT and patients observed after surgery. Patients without any follow-up data were excluded from this analysis. Response to treatment was evaluated through brain MRI, according to RECIST criteria 1.1. LC, iPFS and OS were estimated from the day of surgical intervention using the Kaplan-Meier method and stratified for possible prognostic factors (i.e. adjuvant RT, extent of resection, age, disease site, sex, Karnofsky Performance Status-KPS). Univariate and Multivariate analyses (MVA) were performed by employing the Cox proportional hazards regression model.

Results:

Our retrospective analysis included a total of 128 patients. Of these, 66 were females (52%), with a median age of 63 years and a median KPS of 90 at diagnosis. GTR was achieved in 96 patients (75%) and STR in 32 patients (25%). Sixty-five patients (51%) were observed after surgery, while adjuvant RT was administered in 63 patients (49%). Median prescribed RT dose was 54 Gy (50.40-60 Gy), with a median overall treatment time (OTT) of 44 days. At a median follow-up of 57 months, 5-year LC, iPFS and OS were 76%, 73% and 90% respectively. Compared to patients observed after surgery, those receiving adjuvant RT had higher LC at 5 years (80% vs 70%) and at 7 years (80% vs 46%, p=0.045). Adjuvant RT turned out to be beneficial also in terms of iPFS compared to observation, with a 5-year difference of 11% (78% vs 67%, p=0.050) and a 7-year difference of 30% (78% vs 48%). The advantage of adjuvant RT was more significant in patients who underwent GTR (5-year LC 89% vs 78%, p=0.026; 5-year iPFS 89% vs 75%,