Long-term Efficacy, Survival, and Toxicity of Peptide Receptor Radionuclide Therapy in Patients With Refractory Meningioma

BACKGROUND: Peptide receptor radionuclide therapy (PRRT) offers a promising treatment option by targeting the high density of somatostatin receptors overexpressed in meningiomas. The objective of this study aimed to evaluate the long-term outcome of PRRT in patients with refractory meningioma. PATIENTS AND METHODS: Eighteen patients with refractory meningioma, presenting with progression or recurrence despite surgery or radiotherapy or having inoperable tumors and lack of other therapeutic options, received PRRT with 177Lu-labeled or 90Y-labeled somatostatin analogs (DOTATATE, DOTATOC, or HA-DOTATATE) between January 2004 and December 2019. Treatment response was evaluated according to the Response Assessment in Neuro-Oncology, Response Evaluation Criteria in Solid Tumors, and molecular imaging criteria. RESULTS: Most patients received 2 cycles of PRRT, and up to 4 cycles were applied. The mean total administered activity was 12.7 GBq (range: 8.5-28.5 GBq). Of 14 patients monitored after 2 cycles of PRRT, disease control was reached in 12 (85.7%) patients. The median progression-free survival was 32.3 months, and the median OS has yet to be reached with a median follow-up of 67.1 months. All patients tolerated the therapy without any serious acute adverse effects. No Common Terminology Criteria for Adverse Event grades 2-4 anemia, leukopenia, or thrombocytopenia toxicities were observed during or after PRRT. No renal toxicity, hepatotoxicity, or late radiation adverse effects were reported during long-term follow-up. CONCLUSIONS: PRRT showed promising outcomes in patients with refractory meningiomas, with high disease control and encouraging progression-free survival and OS, and therefore appears to be a favorable therapeutic option. With long-term follow-up, PRRT demonstrated a favorable safety profile, resulting in very few side effects in this cohort of patients with meningioma.