Researchers at the University of Virginia School of Medicine are developing a new technique using focused ultrasound to kill glioblastoma cells, which are 'highlighted' with a fluorescent drug, to treat the deadliest type of brain tumor. VPM’s Charles Fishburne talked with neurosurgeon Dr. Jason Sheehan about the disease and his promising new approach.
Dr. Jason Sheehan:
Glioblastoma is the most common primary brain tumor to adults. And there are approximately 80 to 100,000 new cases of glioblastoma each year in the United States. It's relatively common, because some notable people have been affected by it. Most recent notables Senator Kennedy and Senator John McCain, who... their battle with this type of tumor, glioblastoma was very public, in its nature.
Charles Fishburne:
This tumor is usually fatal, is it not?
Sheehan:
Very few patients will have a cure, but there are some five-year survivors. But the vast majority of these patients, their median survival will typically be around 12 to 18 months from time of diagnosis.
Fishburne:
So what are the difficulties we have in treating it?
Sheehan:
Well, the tumor once it is diagnosed tends to be very invasive of the surrounding brain tissue and the tumor has a tremendous ability to to adapt and to respond and to become resistant to treatment.
Fishburne:
You are researching a possible treatment now that involves using focused ultrasound and a drug called 5 ALA. How does that work?
Sheehan:
So by combining these two relatively innocuous, already FDA-approved approaches, we were able to induce a tumoricidal effect, a killing of the tumor, in a very efficient fashion.
Fishburne:
Tell me about 5-ALA.
Sheehan:
It's a drug. It's a drug that is a fluorescent probe. It, by itself, really doesn't do much of anything other than it lights up the tumor in the operating room.
Fishburne:
It helps you then to locate the spot.
Sheehan:
It not only helps you to navigate but it helps to tell you whether or not you've completely resected the tumor in the operating room. If there's anything else that lights up under this particular wavelength of light, then that would be the remaining tumor. Patients drink it about three hours before their surgery.
They ingest it, it goes up into the brain and it lights up the tumor, allowing the surgeon to be able to more efficiently and and and effectively resect their glioblastoma.
Fishburne:
And the ultrasound basically causes it to start bubbling?
Sheehan:
It does start to generate what are called reactive oxygen species, which are unstable compounds that are generated in the cell that lead to the cell's destruction. And when that's the cancer cell, that's obviously a desirable effect.
Fishburne:
So you consider this a breakthrough.
Sheehan:
Well, we're really excited about the use of this ultrasound and a variety of other brain tumor indications. And I also want to emphasize the importance of clinical trials, one of which we're already offering at the University of Virginia now for focus ultrasound for glioblastomas, and we expect to have many more in the future.