The LCH-IV is an international, multicenter, prospective clinical study for pediatric
Langerhans Cell Histiocytosis LCH (age < 18 years).

This phase I/II trial studies how well tiragolumab and atezolizumab works when given to children and adults with SMARCB1 or SMARCA4 deficient tumors that that has either come back (relapsed) or does not respond to therapy (refractory). SMARCB1 or SMARCA4 deficiency means that tumor cells are missing the SMARCB1 and SMARCA4 genes, seen with some aggressive cancers that are typically hard to treat. Immunotherapy with monoclonal antibodies, such as tiragolumab and atezolizumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread.

This phase II trial studies the best approach to combine chemotherapy and radiation therapy (RT) based on the patients response to induction chemotherapy in patients with non-germinomatous germ cell tumors (NGGCT) that have not spread to other parts of the brain or body (localized). This study has 2 goals: 1) optimizing radiation for patients who respond well to induction chemotherapy to diminish spinal cord relapses, 2) utilizing higher dose chemotherapy followed by conventional RT in patients who did not respond to induction chemotherapy. Chemotherapy drugs, such as carboplatin, etoposide, ifosfamide, and thiotepa, work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Radiation therapy uses high energy x-rays or high-energy protons to kill tumor cells and shrink tumors. Studies have shown that patients with newly-diagnosed localized NGGCT, whose disease responds well to chemotherapy before receiving radiation therapy, are more likely to be free of the disease for a longer time than are patients for whom the chemotherapy does not efficiently eliminate or reduce the size of the tumor. The purpose of this study is to see how well the tumors respond to induction chemotherapy to decide what treatment to give next. Some patients will be given RT to the spine and a portion of the brain. Others will be given high dose chemotherapy and a stem cell transplant before RT to the whole brain and spine. Giving treatment based on the response to induction chemotherapy may lower the side effects of radiation in some patients and adjust the therapy to a more efficient one for other patients with localized NGGCT.

This phase III trial compares memantine to usual treatment in treating patients with primary central nervous system tumors. Memantine may block receptors (parts of nerve cells) in the brain known to contribute to a decline in cognitive function. Giving memantine may make a difference in cognitive function (attention, memory, or other thought processes) in children and adolescents receiving brain radiation therapy to treat a primary central nervous system tumors.

This randomized clinical phase III trial studies how well web-based physical activity intervention works in improving long term health in children and adolescents with cancer. Regular physical activity after receiving treatment for cancer may help to maintain a healthy weight and improve energy levels and overall health.

This study aims to use clinical and biological characteristics of acute leukemias to screen for patient eligibility for available pediatric leukemia sub-trials. Testing bone marrow and blood from patients with leukemia that has come back after treatment or is difficult to treat may provide information about the patient's leukemia that is important when deciding how to best treat it, and may help doctors find better ways to diagnose and treat leukemia in children, adolescents, and young adults.