Improved tumor control with adjuvant radiotherapy in patients with central neurocytoma: a multicenter study

Abstract

Purpose The benefit of external beam radiotherapy (EBRT) over Gamma Knife surgery (GKS) for central neurocytoma (CN) remains unclear. The aim of this retrospective, multicenter study was to investigate the role of adjuvant radiotherapy (ART) after surgical removal of CN and compare the outcomes of these modalities. Methods We included 128 patients with CN who underwent surgery during 2000-2020. Patients were categorized according to the extent of resection, Ki-67 labeling index, and ART modality. Progression-free survival (PFS) was assessed using Kaplan-Meier analysis and Cox proportional-hazards modeling. Results The median tumor size and follow-up duration were 5 cm and 66 months, respectively. ART was independently associated with an improved PFS (p = 0.005). Five-year PFS rates were higher among patients who received EBRT (n = 20, 95.0%), compared to GKS (n = 21, 78.3%, p = 0.061) and no radiotherapy (n = 87, 71.4%, p = 0.035). In the gross total resection and Ki-67 index > 2% subgroups, the PFS was higher in the EBRT group than that in the rest (p = 0.026). In patients with a Ki-67 index <= 2%, no PFS difference was observed between the ART and no-radiotherapy subgroups (p = 0.952). Among patients receiving ART, EBRT resulted in a longer PFS than GKS (p = 0.029 upon multivariable analysis). Conclusions ART may improve tumor control in patients with CN. Even in patients who undergo total resection, ART may be beneficial in the Ki-67 index > 2% subgroup. EBRT may result in superior PFS to GKS among patients with surgically resected CN.