Adjuvant Radiotherapy Versus Surveillance for Grade 2 Intracranial Meningiomas: A Multi-Institutional Propensity Score-Matched Study

Abstract

PurposeWe aimed to compare the outcomes of adjuvant radiotherapy (ART) and surveillance in patients with grade 2 meningiomas (MNG2) who underwent surgical resection.Materials and MethodsData from four hospitals, in which patients aged ≥18 years underwent Simpson grade 1−4 surgical resection for newly diagnosed MNG2 between 1998 and 2018, were examined in this multicenter retrospective cohort study. Patients receiving ART with conventional fractionation were compared with those undergoing surveillance. Progression-free survival (PFS), progression/recurrence (P/R) were evaluated.ResultsThis study included 518 patients, 158 of whom received ART. The median follow-up duration was 64.9 months. In the total cohort, ART was independently associated with significantly improved PFS (HR, 0.35; 95% CI, 0.23–0.55; P<0.001) and P/R (HR, 0.30; 95% CI, 0.18–0.48; P<0.001). In the propensity score-matched cohort (n=143 in each group), the 5-year PFS rates were 80.8% and 57.7% (P=0.004), and the 5-year P/R rates were 16.5% and 40.0% (P=0.002) in the ART and surveillance groups, respectively. After gross total resection, the 5-year PFS (85.0% vs. 64.7%; P=0.020) and P/R rates (15.2% vs. 32.0%; P=0.035) were significantly better in the ART group than in the surveillance group. A model for P/R was developed using recursive partitioning analysis with surgical extent, tumor size, and Ki-67 index. ART reduced the risk of P/R in the low- (P=0.069), intermediate- (P=0.044), and high-risk groups (P<0.001). Local control was also significantly enhanced by ART among all the risk groups (all P<0.05).ConclusionsART significantly improved PFS and P/R in patients with MNG2, irrespective of the surgical extent, and can be recommended after gross total resection. A prognostic model may guide decision-making for the use of ART.

Radiotherapy for meningiomas

“…Including WHO grade 3 meningiomas, local control at 5 years was 86.7% with radiotherapy versus 59.3% without, and progression free survival at 5 years was 73.5% versus 54.9%, respectively. Another group of investigators [ 39 ] more recently expanded on this experience with a multi-institutional study across 4 centers in Korea which included 518 patients with WHO grade 2 meningiomas resected between 1998 and 2018, 158 of whom received adjuvant radiotherapy, again finding improved progression freedom with radiation (80.8% at 5 years compared to 57.7% after surgery alone). Radiotherapy improved outcomes following gross total resection, as well as across all clinical risk strata devised by the authors.…”

Radiotherapy intensification for atypical and malignant meningiomas: A systematic review

“…Merging retrospective data from 4 different hospitals, Byun et al 30 proposed a risk stratification model based on 3 factors: tumor size, surgical extent, and Ki-67 labeling index. ART significantly improves PFS in patients with G2 meningiomas, irrespective of the risk category.…”

“…The trial compared GTR versus STR regardless of grading and escalated to higher doses only STR lesion. 16 The relevance of radical surgical removal has only been described retrospectively in G2 meningiomas 30 , 27 , 25 and in fact the trial was powered to demonstrate a 3-year PFS > 70% in the G2 GTR group which had received 60 Gy in 30 fractions. Due to the very limited number of patients with G3 GTR and G2–G3 STR, the results of this trial were inconclusive for the other patient subgroups.…”

The Korean Society for Neuro-Oncology (KSNO) Guideline for the Management of Brain Tumor Patients During the Crisis Period: A Consensus Survey About Specific Clinical Scenarios (Version 2023.1)

“…Furthermore, for 82-year-old elderly patients, most respondents also recommended surveillance after gross total resection. This is probably due to the relatively high local control around 70% at 5 years [ 23 ], and the consideration of the shortage of medical resources. In contrast, despite the shortage of radiotherapy resources, most respondents chose to proceed with adjuvant radiotherapy in patients with completely resected tumor but high mitotic counts.…”