When is the Best Time to Seek a Clinical Trial for Glioblastoma?

For some people with glioblastoma brain tumors, enrolling in a clinical trial enables access to cutting-edge treatment. Here, our Curious Dr. George talks clinical trials with Cancer Commons Expert Physician Advisor, Eric T. Wong, MD. Dr. Wong is also Associate Professor of Neurology at Harvard Medical School and Co-Director of the Brain Tumor Center at Beth Israel Deaconess Medical Center.

Curious Dr. George: Malignant brain tumors are often treated initially by surgery and follow-up radiation. However, many recur and progress. Glioblastoma patients have many treatment options from which to choose, including clinical trials. But when is the best time to look for a clinical trial? Prior to initial therapy, immediately after initial treatment, or upon recognized tumor progression? How should a patient and their physician seek the most appropriate clinical trials?

Dr. Wong: This is a very important question for adult patients with glioblastoma and for a clinical neuro-oncologist like me who cares for them. At the time of diagnosis, the tumor is unstable and it is often difficult to determine the extent of microscopic spread to the adjacent brain. This is because glioblastoma is an infiltrative disease. Although MRI scans allow us to visualize the tumor, there are still microscopic tumors that we cannot see on head MRI scans. I always have to watch out for microscopic tumors causing motor or language dysfunctions.

Radiation is the mainstay of glioblastoma treatment, and it takes 6 weeks to administer. The reason is that we can only give a small fraction of radiation daily because normal brain and nerve cells cannot handle large fractions of radiation. The total dose needed to control the tumor is also at the maximum of brain tolerance. It takes at least 4 to 5 weeks to accumulate enough radiation dosage to exert an effect on the glioblastoma to halt tumor growth. Therefore, it is often a misconception that once radiation is started, tumor growth is controlled. In fact, the tumor can still grow during the initial 4 to 5 weeks of radiation, and it is not until the last week of 1.5 weeks that the radiation exerts its full effect on halting tumor progression.

For these reasons, it is often difficult to find a trial that fits a newly diagnosed patient with glioblastoma without delaying radiation. This is a logistics problem—a patient needs to be at the right time and right place where a clinical trial is available for them, and radiation can still be initiated within 4 to 6 weeks after surgery. It is my opinion that if a clinical trial cannot be found in a timely fashion, the patient should take conventional treatment. The time to look for clinical trials is when the tumor is stabilized with radiation and temozolomide.

After radiation and temozolomide, the patient goes into the adjuvant phase of treatment with monthly adjuvant temozolomide and monitoring with periodic head MRI scans. It is during this period that the patient has more time to look for a clinical trial in the event of recurrence or disease progression.

If you are at this point and looking for a trial, ask a family member to help you navigate the clinicaltrials.gov website or contact Cancer Commons and work with our Scientists to find a promising trial. At this point, you will also have more time to think about traveling and lodging in a faraway city, while talking to your neuro-oncologist about options. You and your care team should look at the inclusion and exclusion criteria to see if you fit into a particular trial. If none fits, your treating neuro-oncologist can still develop a personalized treatment for you.

Dr. Wong can be reached at ewong@bidmc.harvard.edu.

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