Cracking the code to brain cancer treatment might start with cracking the brain’s protective shield.
Nearly impenetrable walls of jam-packed cells line most of the brain’s blood vessels. Although this blood-brain barrier protects the organ from harmful invaders, it also prevents many medications from reaching the brain.
Now, scientists can get a powerful chemotherapy drug into the human brain by temporarily opening its protective shield with ultrasound and tiny bubbles. The early-stage clinical trial, described May 2 in the Lancet Oncology, could lead to new treatments for those with brain cancer.
Better treatments are especially needed for glioblastoma, a common and aggressive type of brain tumor. Even after surgical removal, another mass tends to grow in its place.
“There’s really no established treatment for when the tumors come back,” says neurosurgeon Adam Sonabend of the Northwestern University Feinberg School of Medicine in Chicago. Patients with recurrent glioblastomas “don’t have any meaningful therapeutic options, so we were exploring new ways of treating them.”
After the initial tumor has been removed, patients typically receive a relatively weak chemotherapy drug that can bypass the brain’s barricade. More potent drugs could help destroy any lingering disease — if the medicines could break through the barrier.
Sonabend and colleagues turned to an exploratory method using ultrasound that has already succeeded at briefly opening the blood-brain barrier in humans (SN: 11/11/15). A person first receives an intravenous injection of a fluid brimming with microscopic bubbles, which fill the body’s blood vessels. This technique is already routinely used to help visualize vessels in ultrasound imaging. In the targeted brain area, ultrasound waves shake the microbubbles, prying open the densely packed blood vessel walls.
To examine safety and dosing of this delivery method and drug, 17 people had their regrown…
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