Testing Proton Craniospinal Radiation Therapy Versus the Usual Radiation Therapy for Leptomeningeal Metastasis, RADIATE-LM Trial

Inclusion Criteria: * PRIOR TO STEP 1 REGISTRATION * Patients with pathologically (histologically or cytologically) proven diagnosis of breast cancer or NSCLC * Patients must have newly diagnosed leptomeningeal metastasis established through at least one of the following: * Positive CSF cytology for malignancy * CSF cytology with suspicious cells is considered positive; CSF cytology with atypical cells is considered equivocal and not positive * Patients with an equivocal or negative CSF cytology result, or not suitable for CSF sampling, radiographic diagnosis of leptomeningeal metastasis with linear and/or nodular disease and documentation of typical clinical signs (European Association of Neuro-Oncology \[EANO\]-European Society for Medical Oncology \[ESMO\] Diagnostic Criteria Type IIA-IIC) is required * Patients with typical clinical signs of leptomeningeal metastasis may have one or more of the following symptoms and signs: headache, nausea, vomiting, mental status change, gait difficulty, cranial nerve palsy, diplopia, visual change, hearing loss, radicular weakness, radicular sensory change, urinary retention, saddle anesthesia, constipation, neck pain, and back pain * For patients with prior history of immunotherapy or current immunotherapy, CSF sampling rather than just MRI enhancement is strongly recommended to exclude immune-related aseptic meningitis * Patients must be candidates for radiation therapy for the treatment of leptomeningeal metastasis…