Involved-field Radiotherapy with Intrathecal-MTX or Intrathecal-Ara-C for Leptomeningeal Metastases

This is a phase 2 clinical trial that aims to compare two different treatments for leptomeningeal metastases, a condition where cancer from a solid tumor spreads to the thin layers of tissue that cover the brain and spinal cord. The trial involves patients who will receive either involved-field radiotherapy with concurrent intrathecal-MTX or intrathecal-Ara-C. The goal of this study is to find a more effective treatment for this condition, potentially improving care and addressing current challenges faced by patients. During the trial, participants will undergo a combination of radiotherapy and intrathecal chemotherapy. The radiotherapy involves fractionated, conformal radiation given at a daily dose of 2 Gy, targeting sites of symptomatic disease, bulky disease observed on MRI, including the whole brain and basis cranii received 40 Gy in 20 fractions and/or segment of spinal canal received 40-50 Gy. The intrathecal chemotherapy is administered via lumbar puncture, with either MTX 15 mg plus dexamethasone 5 mg, or Ara-C 50mg plus dexamethasone 5 mg, once per week for 4 weeks. The clinical response is assessed using the RANO proposal for response criteria of LM disease.