Clinical Course for DIPG
Once the diagnosis of a DIPG is suspected, anti-inflammatory steroids (such as dexamethasone) are usually started. The steroids can improve symptoms quickly by decreasing the swelling associated with the tumor. Steroids can cause side effects including increased moodiness, agitation, weight gain, increased appetite and high blood pressure and blood sugar. These last two side effects can be controlled with medication, if they become severe.
The only treatment that is routinely recommended for the treatment of all children with a DIPG is x-ray radiation therapy (XRT). XRT can be given either alone or with chemotherapy and usually takes 4 to 6 weeks to complete. Side effects during radiation can include mild nausea and fatigue.
Many chemotherapeutic drugs have been tried for DIPG, with studies looking at the use of chemotherapy before XRT, during XRT, immediately following XRT, and at the time of tumor progression. The results have been disappointing, with no drug(s) to date improving survival. While pediatric oncologists continue to develop new therapies for DIPG, the mainstay of current treatment remains XRT. There are ongoing clinical trials for DIPG, which allow new drugs to be tested in this disease. While there are always risks when enrolling in clinical trials, they are the best way to get your child the most promising new medications and to make sure the pediatric oncology community learns all it can about what therapies work best for DIPG.
Most DIPG tumors in the beginning respond to a combination of radiation and steroids. The child’s neurologic deficits will very often decrease and may disappear completely. Over the course of weeks to months, the steroids can be decreased and then stopped in many cases. The child can often return to school, take special trips, and almost return to normal life. During this time, the child has regular MRI scans to measure the regression of the tumor and monitor if the tumor is coming back.
In almost all cases, after about 6 to 12 months, the DIPG tumor starts to grow again. Sometimes the neurologic symptoms are the same as when the child was first diagnosed with DIPG. Sometimes new nerves and systems are affected. The child will often begin to show neurologic symptoms even if the MRI scan of the tumor appears largely unchanged.
Once the tumor has started to grow again, no further treatment has been shown to improve survival. When children start to have neurologic symptoms, they are often restarted on steroids. This treatment can sometimes improve symptoms for a short time. However, the tumor will continue to grow, and even if the steroid doses are increased, the child’s symptoms will continue to worsen. Eventually the tumor grows until it affects nerve centers that are important for swallowing, breathing, and controlling heartbeat.
If the tumor is blocking the flow of cerebrospinal fluid (CSF), some parents—in discussion with the doctors—may decide to have a neurosurgeon place a VP-shunt to help with pressure symptoms. A VP-shunt is a flexible plastic tube that bypasses the blockage in the brainstem and allows the CSF fluid to pass out of the skull. Neurosurgeons place the shunt into the fluid cistern in the brain, and then pass it out of the skull, under the skin, and to the abdomen, where the CSF is absorbed. This procedure can improve some of the headache and nausea symptoms of increased intracranial pressure, and it can extend the life of children with DIPG; it does not, however, change the ultimate outcome.
Only very few children are long-term survivors of DIPG. Because biopsies are not performed on these children with typical appearing DIPGs, it is unclear whether or not they actually had DIPG to start with, or in fact had a different tumor or condition that looked like a DIPG on the MRI. There is no one treatment that these children received that set them apart from the vast majority (more than 95 percent) of children who die from DIPG. Pediatric oncologists are actively looking for new treatments and are trying to learn more about DIPG. They hope that by learning more from tumor tissue taken at autopsy from children who die from DIPG they can help children who develop DIPG in the future.