SSTR-directed peptide receptor radionuclide therapy for recurrent meningiomas: analysis of safety, efficacy and prognostic factors.

Abstract

This study evaluates safety and efficacy of peptide receptor radionuclide therapy (PRRT) as a stand-alone treatment for recurrent meningiomas and investigates the prognostic value of laboratory markers and quantitative PET parameters. The single-center study includes 32 patients with recurrent meningioma, who underwent PRRT with [¹⁷⁷Lu]Lu-DOTATOC/-TATE. Pre-treatment assessments comprised [⁶⁸ Ga]Ga-DOTATOC PET imaging, routine hematology and serum chemistry analysis. Outcomes including progression-free survival (PFS), overall survival (OS), and treatment related toxicity, were retrospectively evaluated using Kaplan-Meier survival analysis and Cox regression models. PRRT showed only mild hematological and renal toxicity, with most adverse events being low-grade (87%). OS was significantly shorter in patients with WHO grade III meningiomas (10 months) compared to grade I (not reached, HR 4.77, p < 0.01) and grade II (47 months, HR 4.05, p = 0.01). Similarly, PFS was shorter in patients with WHO grade III meningiomas (4.5 months) compared to grade I (17 months, HR 6.47, p < 0.001) and grade II (17 months, HR 2.71, p = 0.02). In multivariable analysis, only higher WHO grade was an independent predictor of disease progression, while baseline PET and laboratory parameters showed no consistent association. Furthermore, increase of SSTR-positive tumor volume in follow-up PET was associated with shorter PFS (HR 1.02, p = 0.02). PRRT is a safe treatment option and appears to have a favourable effect in patients with recurrent meningiomas. WHO tumor grade is the strongest predictor of PFS and OS, while baseline PET parameters appear to have no prognostic value.