Diffuse Intrinsic Pontine Glioma (DIPG) Radiation Treatment - DIPG Resource Network

Keith Desserich from The Cure Starts Now and Dr. Trent Hummel outline the radiation as treatment for DIPG. Learn more at https://dipg.org/dipg-treatment/radia...

Radiation therapy is the standard treatment for children with diffuse intrinsic pontine gliomas (DIPGs). This type of therapy uses high-energy x-rays, similar to those used in a computed tomography (CT) scanner but at much higher doses. These x-rays deposit energy within the tumor, causing damage to the DNA of cells. The tumor cells are then unable to repair the damage, and ultimately die when the tumor cells try to divide.

Before starting radiation, parents of a child with a DIPG consult with the radiation oncologist to discuss the planned therapy and potential side effects. After this initial consultation, the child undergoes a planning session (also referred to as a simulation). At that time, a mask will be custom-made for the child. The mask allows accurate, consistent positioning of the head for each treatment and helps the child remain still during treatment. The mask is made out of a special type of plastic that becomes moldable when heated in a water bath. After the mask is completed, a special CT scan is performed. This entire process takes approximately 1 hour.

After the planning session, the radiation oncologist uses the CT scan to define the area that corresponds to the tumor and the regions of the brain that should not receive radiation. With the assistance of dosimetrists (who specialize in calculating the dose of radiation to ensure the tumor gets enough radiation) and physicists (who develop and direct quality-control programs for radiation equipment and procedures), a radiation therapy plan is developed to maximally treat the tumor while minimizing the amount of radiation delivered to normal brain tissues and surrounding tissues.

Radiation therapy is an effective palliative treatment that improves symptoms in about 80% of children with DIPGs, prolonging their survival by 2-3 months. The dose of radiation therapy is limited by the tolerance of the surrounding normal brain tissue. However, given the high rate of response, in the 1980’s a number of institutions increased the dose of radiation therapy from 54 Gy to greater than 70 Gy and had promising preliminary results. To escalate the dose of radiation delivered, smaller doses per treatment were used (referred to as hyperfractionation). These smaller doses allow greater recovery of normal tissues, and thus a higher total dose can be given. However, a Pediatric Oncology Group randomized trial showed that while the higher dose of radiation was well tolerated by most children, there was unfortunately no difference in survival rates.