Preventing thyroid damage in children receiving cancer radiation therapy

This trial is testing whether L-thyroxine (a thyroid hormone medication) can protect the thyroid gland during radiation therapy for certain childhood cancers like medulloblastoma and lymphoma. Half of the children in the study will receive the medication starting 2 weeks before radiation and continuing through treatment, while the other half will receive standard care without the medication. The goal is to prevent a common side effect called hypothyroidism, where the thyroid stops working properly after radiation.

Radiation therapy to the chest and neck area often damages the thyroid gland in children, causing them to develop hypothyroidism—a condition where the thyroid cannot produce enough hormones. This study is testing whether the medication can protect the thyroid during radiation and prevent this lifelong complication.