Diffuse Intrinsic Pontine Glioma | Diagnosis & Treatment

How is diffuse intrinsic pontine glioma diagnosed? 

The first step in treating your child is forming an accurate and complete diagnosis. Diffuse intrinsic pontine glioma (DIPG) is most commonly diagnosed from imaging studies.

Your child’s doctor will perform a complete medical and physical examination. In addition, your child’s physician may order some of the following imaging tests:

How are DIPGs classified?

There are four stages of gliomas, according to how the cells look under a microscope. Ordered from least severe to most severe, they are:

Low grade:

  • pilocytic (grade I)
  • fibrillary (grade II)

High grade:

  • anaplastic (grade III)
  • glioblastoma multiforme (grade IV)

When DIPGs are biopsied, they are usually grade III or grade IV. Occasionally they are grade II, but, because of their location in the brain, they are still considered malignant. These are very aggressive tumors and grow by invading normal brain tissue.

How are DIPGs treated?

Your child’s physician will determine a specific course of treatment based on several factors, including:

  • your child's age, overall health, and medical history
  • type, location, and size of the tumor
  • extent of your child’s disease
  • your child's tolerance for specific medications, procedures, or therapies

A number of treatments may be recommended. Some of them help to treat the tumor while others are intended to address complications of the disease or side effects of the treatment. Treatment for DIPG may include radiation therapy.

Radiation therapy

Radiation is the traditional therapy for newly diagnosed DIPGs, using high-energy rays (radiation) from a specialized machine to damage or kill cancer cells and shrink tumors. Conventional limited-field radiation produces responses in more than 90 percent of children with DIPGs. These responses are short-lived, however, lasting about six to nine months on average. Several trials to increase the dose of radiation therapy have been performed and none have improved survival.

Experimental chemotherapy

Biologic therapy and chemotherapy, in combination with radiation therapy, are actively being investigated as a treatment for DPG. Several trials evaluating new agents are either underway or have been recently completed. With a biopsy of the tumor at diagnosis, the selection of drugs targeted to your child’s tumor can be determined. Multiple clinical trials have demonstrated that routine chemotherapy does not increase survival rates for this condition.

Surgery

Complete surgical removal is not an option in the treatment of these tumors, because of their location in the brainstem. Surgery in this part of the brain can cause severe neurological damage and affect the body’s most vital functions and only biopsies can be performed safely.