CHRISTOPH BURGSTEDT/SCIENCE PHOTO LIBRARY
Researchers have made an important breakthrough after discovering a revolutionary way to treat breast cancer when it spreads to the brain.
For the first time in the world, the new method could provide a non-invasive way to temporarily open the boundaries of the brain to allow antitumor drugs to target cancer. The brain is protected by a layer of specialized cells called the blood-brain barrier, allowing needed substances such as oxygen and sugar while keeping toxins out. But now, scientists have been able to use advanced ultrasound technology to temporarily and non-invasively open the blood-brain barrier in patients with breast cancer that has spread to their brains.
The study included four women with HER2-positive breast cancer that had spread to the brain.
In HER2-positive breast cancers, the cancer cells carry a protein (HER2) that causes them to grow. But some medications, such as trastuzumab (Herceptin), help target this protein.
By temporarily opening the boundaries of the brain, Herceptin was able to target a patient’s brain tumors.
Using ultrasound-assisted magnetic resonance imaging, if the blood-brain barrier appears as a plastic wrap, the researchers said the technique “breaks down” the plastic wrap in certain places, giving the drug an outlet to enter the brain.
The researchers said the port of entry closed within 24 hours. There have been indications that this technique increases the amount of drug that reaches the brain tumor.
But according to the researchers, the results are preliminary and represent only a “proof of concept”.
“We are in the first phase, demonstrating that this is possible and safe,” said Dr. Nir Lipsman, lead study author and a neurosurgeon at Sunnybrook Health Sciences Center in Toronto. But the researchers said a relatively small amount of Herceptin can penetrate the brain.
The ultimate goal, Lipsmann added, is to see if this technique improves long-term control of brain tumor growth, and could help extend survival rates.
A number of drug combinations, including Herceptin, have “activity” against brain tumors in HER2-positive breast cancer patients, said Dr. Charles Shapiro, a professor and oncologist at Icahn College of Medicine, Mount Sinai in New York.
When the cancer has spread to the brain, he said, the blood-brain barrier is really “blurred”.
The results were published October 13 in the journal Science Translational Medicine.