This pilot trial compares drug exposure levels using a new method for dosing vincristine in infants and young children compared to the standard dosing method based on body surface area (BSA) in older children. Vincristine is an anticancer drug used to a variety of childhood cancers. The doses anticancer drugs in children must be adjusted based on the size of the child because children vary significantly in size (height, weight, and BSA) and ability to metabolize drugs from infancy to adolescence. The dose of most anticancer drugs is adjusted to BSA, which is calculated from a patients weight and height. However, infants and young children have more severe side effects if the BSA is used to calculate their dose, so new dosing models have to be made to safely give anticancer drugs to the youngest patients. This new method uses a BSA-banded approach to determine the dose. Collecting blood samples before and after a dose of the drug will help researchers determine whether this new vincristine dosing method results in equivalent drug levels in the blood over time in infants and young children compared to older children.

In this observational study researcher want to learn more about the effectiveness of drug
VITRAKVI (generic name: larotrectinib) and how well the drug is tolerated during routine use
in patients with TRK fusion cancer which is locally advanced or spread from the place where
it started to other places in the body. TRK fusion cancer is a term used to describe a
variety of common and rare cancers that are caused by a change to the NTRK (Neurotrophic
Tyrosine Kinase) gene called a fusion. During this fusion, an NTRK gene joins together, or
fuses, with a different gene. This joining results in the activation of certain proteins (TRK
fusion proteins), which can cause cancer cells to multiply and form a tumor. VITRAKVI is an
approved drug that blocks the action of the NTRK gene fusion. This study will enroll adult
and paediatric patients suffering from a solid tumor with NTRK gene fusion for whom the
decision to treat their disease with VITRAKVI has been made by their treating physicians.
During the study, patients' medical information such as treatment information with VITRAKVI,
other medication or treatments, changes in disease status and other health signs and symptoms
will be collected within the normal medical care by the treating doctor. Participants will be
observed over a period from 24 to 60 months.

This trial studies health outcomes after treatment in patients with retinoblastoma. Gathering health information over time from patients and family members through vision assessments, samples of tissue and saliva, and questionnaires may help doctors learn more about what causes retinoblastoma, identify long-term health outcomes for patients with retinoblastoma, and find out which therapies may be the best for treating retinoblastoma.

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.