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Elizabeth Maher, M.D., Ph.D. Answers Questions On Glioma

Elizabeth Maher, M.D., Ph.D. Answers Questions On: Glioma

What exactly is a glioma, and how is it related to other brain tumors?

Glioma is basically an umbrella term for tumors of the glia, the cells that provide the physical support for the thinking cells, the neurons. Gliomas are categorized according to which types of glia cells they affect – astrocytes, oligodendrocytes, or both.

Additionally, there are four grades of glioma. Grade 1 is pediatric, often curable by surgery. As you go up the scale through Grades 2, 3, and 4, the gliomas are increasingly aggressive. Grade 4 is the aggressive type of glioma known as glioblastoma multiforme, which typically affects older adults.

I primarily focus on Grade 2 gliomas, which are generally found in teenage and young adult patients. Although they are less aggressive malignancies, low- and intermediate-grade gliomas will eventually progress to glioblastomas if left untreated.

What are the risk factors for developing glioma?

We don’t really know what causes glioma. Most patients do not have a family history. People were frightened for some years that perhaps heavy use of cell phones was a contributing factor, but we now know that cell phones are not a cause. Patients just have a molecular predisposition, and something activates the tumor.

How have recent discoveries affected your approach to diagnosis and treatment of brain tumors?

We have made great strides in understanding these malignancies and developing new clinical tools to treat them. In 2008 a gene called isocitrate dehydrogenase, or IDH, was found to be mutated in 80 percent of patients with low-grade gliomas that developed high-grade tumors. About 10 percent of people with glioblastomas have this mutation. For reasons we do not yet understand, the prognosis for patients with this mutation is much better. Identifying the mutation is both diagnostic and prognostic.

Cells with the IDH mutation produce a metabolite called 2 hydroxygluterate or 2HG in very high concentrations. We have developed a technique to visualize 2HG via magnetic resonance spectroscopy as an imaging biomarker for gliomas. Currently, UT Southwestern is the only cancer center in Texas that is using this specialized imaging technique as a critical tool in managing IDH-mutant gliomas.

Our diagnostic process combines the clinical presentation with advanced imaging and the growing understanding of the basic science behind these tumors. This allows us to provide a truly personalized analysis of a patient’s specific tumor subtype and the biological and molecular factors driving that tumor. Then we put it all together into a customized treatment plan.

Clinical trials are key to improving treatment options for these malignancies. Our patients often participate in research scans and translational studies on top of their usual diagnostic procedures and treatments. They understand that the root of the cure lies in the science. For example, we are part of a focused effort on developing a novel chemotherapy that targets the IDH mutant enzyme. It is a very innovative approach – the first time we have had a drug that could work in non-dividing cells.

The outlook for people with the high-grade gliomas known as glioblastomas is also improving. Thanks to novel chemotherapy and radiation therapy regimens, we have far more long-term glioblastoma survivors than ever before. They tolerate their treatments very well and can continue in their jobs and lives.

When you counsel patients with indolent low-grade brain tumors to be patient and not rush into treatment, how do you help them cope with their symptoms?

Seizures are typically managed well with anti-seizure medicines. We know exercise is very beneficial; for patients who want to work, going back to work is also beneficial. We are much more aggressive than we used to be with physical therapy, speech therapy, and occupational therapy, because these modalities can go a long way toward relieving the original symptoms. Finally, management of the psychological effects of the diagnosis and treatment is very important. This extends to the patient’s family as well since the impact of a brain tumor is felt in all aspects of a family’s life and life plan.