What are “DIPG” Brain Stem Tumors?
The brain stem is the bottom most portion of the brain, connecting the cerebrum with the spinal cord. It consists of the midbrain, pons and medulla located deep in the posterior part of the brain. Tumors that arise along these structures are called brain stem gliomas. Most brain stem gliomas occur in the pons which is the middle of the brain stem ("pontine gliomas") and are diffusely infiltrating, or they grow amidst the nerves. The pontine tumors have a poorer prognosis than the less common midbrain and medullary gliomas. They account for 10% - 15% of all pediatric brain tumors.
Diffuse Intrinsic Pontine Glioma ("DIPG") brain stem tumors affect the cranial nerves, causing symptoms related to the nerves that supply the muscles of the eye and face, and muscles involved in swallowing. These symptoms include double vision, inability to close the eyelids completely, "drooping" on one side of the face, and difficulty chewing and swallowing. The tumor also affects the "long tracks" of the brain, with resultant weakness of the arms or legs and difficulty with speech and walking. Symptoms usually worsen rapidly because the tumor is rapidly growing. The patient's symptoms often improve dramatically during or after six weeks of radiation. Unfortunately, problems usually recur after six to nine months, and progress rapidly. Survival past 12 to 14 months is uncommon, and new approaches to treating these tumors are urgently needed.
Surgery is not generally possible because these tumors (particularly DIPGs) are widely spread within the brain stem and cannot be removed. Radiation therapy has been the main treatment approach, but clinical trials are being used as well. Long term affects are being studied.
To improve the outcome of pontine gliomas, researchers are studying drugs that may enhance the effect of radiation therapy.