Update in Neuro-oncology

APRIL 28, 2009
Todd Kunkler
In a wide-ranging review of the evidence base for the current standard of care for primary brain tumors and other central nervous system malignancies delivered yesterday at the 61st Annual meeting of the American Academy of Neurology, Amy A. Pruitt, MD, touched on a variety of topics in neuro-oncology, including an overview of the epidemiology and diagnosis of primary brain tumors.

Key takeaway points:

When caring for a newly diagnosed, frightened patient who has many questions, neurologists must have compassionate, evidence-based knowledge in order to provide correct answers to the litany of questions patients may ask (“Is it benign or malignant?” “Is it hereditary?” “What’s going to happen?” “Where should I go for treatment?”)

Even if neurologists are prepared with a comprehensive array of educational resources, patients will still go online and look for information on diagnosis and treatment. Googling “Brain tumors” returns all manner of information—some good, some incorrect, and some misleading—which can have an adverse effect on the patient’s decision-making process. Neurologists must be aware of the easy availability of misinformation and be prepared to vet these sites for their patients.

Current treatment for glioblastoma is temozolomide. Approved in 2005 for up-front therapy for glioblastoma, it is a well-tolerated oral drug. The problem is that it is extremely expensive, and oral therapies are dealt with differently from IV therapies with respect to coverage.

The evidence reveals a nearly 50% two-year survival rate among patients who have the methylated MGMT promoter gene and who are treated with temozolomide and radiation. Patients in this group who are younger than age 50 years achieve a 28% four-year survival rate. Neurologists can say to scared patients upon diagnosis that there is some hope and that there is a very different picture than existed a few years ago.

Class 1 evidence shows that patients diagnosed with glioblastoma should be given prophylactic treatment for pneumocystis; they should have a PPD put on; they should not be given AEDs unless they have seizures; they should receive flu vaccinations; they should receive perioperative DVT prophylaxis; they should receive calcium and vitamin D supplements if they have been on steroids for a long time; and they should be screened for hepatitis B.

Neurologists should be cognizant of signals for, characteristics of, and potential impact on diagnostic and treatment decision-making processes for chemo-radiation-induced tumor pseudoprogression.

The front-line use of molecular markers for predicting treatment response and outcome “represents a paradigm shift in neuro-oncology.” The RTOG and EORTC trials in particular are powerful examples of this (they looked at the prognostic utility of the 1p and 19q co-deletions in patients with anaplastic oligodendrogliomas. These markers confer a better prognosis and durable response to chemotherapy).

Even in instances of optimal treatment, nearly all high-grade gliomas recur.

Once-promising treatment strategies for treating recurrent high-grade tumors are being replaced by several new investigational approaches, including regimens combining temozolomide with several other agents, and noncytotoxic therapies that target “particular molecular aberrations” in tumor cells (including agents that target EGFR overexpression and anti-VEGF agents like bevacizumab).

Anti-VEGF therapy is associated with several potential complications, including a change in tumor recurrence patterns, hypertension, RPS, DVT, and wound dehiscence.

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