68Ga-Dotatate PET and MRI Guided Radiation Dose Escalation for High Risk Meningioma

Patient will be enrolled, and dose selected per modified toxicity probability interval utilizing a Bayesian Optimal interval suite to maximize the probability that selecting the MTD dose that has a target DLT rate under 30% while optimizing patient safety over the 3+3 trial design 15. For our initial cohort the investigators will seek to treat 3 patients at 69 Gy in 30 daily fractions, Monday-Friday for 6 weeks of treatment utilizing MRI/PET target delineation with IMRT/VMAT. Patients will be followed weekly for on-treatment visits and 30 days from end of radiation to evaluate for DLTs classified as grade 3+ toxicity by NCI-CTCAE v5.0. Subsequent dosing will be determined by DLTs experienced utilizing a modified toxicity probability interval design. If the stopping rule is met, the trial will discontinue enrollment and select the MTD. If the stopping rule is not met, the DLT rate will be computed at the current treated dose. DLT rate is calculated by the total number of patients experiencing DLT at the current dose divided by total number of evaluable patients at the current dose. With a DLT rate of less than or equal to 0.236 dose will be escalated by 3 Gy, DLT rate greater than 0.359 will de-escalate the dose by 3 Gy. A rate between 0.236 and 0.359 will retain the current dose. An additional 3 patients will then be enrolled at specified dose depending on DLT rate. Patients will be treated and followed to assess for acute DLTs. The process will be repeated with enrollment discontinued if stopping rule met or additional patient will be enrolled at a dose from 66 - 75 Gy in 30 fractions based on new DLT rate. Enrollment utilizing DLT rate will be discontinued once stopping rule met or 12 patients are enrolled and an MTD will be established. Once the MTD has been established, an additional 12 patients at the MTD will then be enrolled. Following radiation treatment (with once weekly on-treatment visits) and evaluation 1 month following completion for radiation, patients will be evaluated 3-, 6-, 9, 12-, 18-, and 24-months post-treatment utilizing NCI-CTCAEv5.0, symptom burden and QOL questionnaires, and MRI imaging to evaluate for safety, toxicity, and treatment efficacy. The study population will include any adult patients, with high-risk meningioma as defined by RTOG definition (Grade 2 meningioma with subtotal resection or recurrence, and any Grade 3 meningioma). It is believed dose escalation with IMRT/VMAT therapy is feasible and well tolerated with improved target delineation utilizing both MRI and PET fusion with an acceptable toxicity profile.