Stupp Treatment With Intrathecal Injection of Thiotepa for Glioblastoma With Advanced Spread

This trial is testing whether adding a chemotherapy drug called thiotepa (injected into the spinal fluid) to the standard brain cancer treatment (Stupp protocol: radiation plus temozolomide chemotherapy) improves outcomes for people with newly diagnosed grade 4 brain tumors that have spread into the fluid-filled spaces of the brain or spinal cord. **You may be eligible if...** - You are between 18 and 75 years old with a newly diagnosed WHO grade 4 brain tumor (such as glioblastoma) - Imaging suggests your tumor has invaded the ventricles or the lining of the brain (meninges) - Cancer cells were found in your cerebrospinal fluid (spinal fluid) before radiotherapy - Your surgery involved opening a ventricle or fluid-filled space in the brain - Your general health score (ECOG) is 0–2 and your expected survival is at least 3 months - Your blood counts and organ function meet the required levels **You may NOT be eligible if...** - Your tumor has not spread into ventricular or meningeal spaces - No cancer cells were found in your spinal fluid - Your blood counts, liver, or kidney function are outside the required ranges Talk to your doctor to see if this trial is right for you.