Investigating the clinical significance of systemic inflammatory indices for post-treatment peritumoral edema after gamma knife radiosurgery for meningioma

Abstract

Background: Gamma knife radiosurgery (GKRS), a noninvasive and highly precise treatment modality, is widely utilized in the management of meningiomas. Despite its efficacy, post-treatment peritumoral edema (PTE) remains a significant clinical concern. Although systemic inflammatory indices in peripheral blood have been associated with brain edema, their association with post-GKRS PTE in meningioma has not been elucidated. This study investigated the potential risk factors for post-GKRS PTE in patients with meningiomas, with a specific emphasis on the role of peripheral blood-related systematic inflammatory indices.

Methods: We retrospectively analysed 129 patients with meningioma (maximum diameter < 3 cm, no preexisting PTE or mass effect) who underwent primary single-session GKRS between September 2019 and December 2022. Baseline characteristics, systemic inflammatory indices, tumour characteristics, and dosimetric parameters were collected. The primary outcome was radiologically confirmed PTE during follow-up. Univariate analysis, multivariate logistic regression, ROC analysis, Kaplan‒Meier survival analysis, and volume-stratified subgroup analysis with interaction testing were performed. Statistical significance was defined as a two-sided P value < 0.05.

Results: Compared with the non-PTE group, the PTE group had a larger meningioma volume and a higher PLR upon admission. Receiver operating characteristic (ROC) curve analysis revealed a cut-off value of 91.7 for the PLR, with a sensitivity of 0.927, a specificity of 0.446, and an area under the curve (AUC) of 0.667 for predicting the occurrence of post-GKRS PTE. Subgroup analysis revealed that for tumours > 3.6 cm³, only the PLR was a risk factor for PTE (OR = 1.06, P = 0.008), whereas in smaller tumours, only age was associated with PTE (OR = 0.93, P = 0.037). Compared with the smaller-volume/lower-PLR group, the larger-volume/higher-PLR group and the smaller-volume/higher-PLR group had significantly higher PTE risk (OR = 41.5, 95% CI 4.6-374.4; P = 0.0009; and OR = 9.3, 95% CI 1.1-78.4; P = 0.04, respectively), with no significant volume × PLR interaction (P = 0.66). Multivariate logistic regression analyses revealed that a high PLR (OR = 1.02; P = 0.043) was an independent risk factor for post-GKRS PTE. Kaplan-Meier survival curves further indicated that a PLR greater than 91.7 was associated with an increased risk of post-GKRS PTE.

Conclusions: In summary, the results indicated that the PLR may be a simple, effective and easily obtained biomarker for the early identification of patients at high risk of post-GKRS PTE. However, the results require validation through multicentre, prospective studies that include more potential influencing factors.

Keywords: Gamma knife radiosurgery; Meningioma; Peritumoral edema; Platelet-to-lymphocyte ratio.