Neurosurgeons using lasers to treat brain cancer have discovered that the technique breaks down the blood-brain barrier, a finding that could lead to new treatment options for patients with the deadly disease.

The blood-brain barrier is sort of a natural “security system” that shields the brain from toxins in the blood but also blocks potentially helpful drugs such as those used in chemotherapy.

“We were able to show that this blood-brain barrier is broken down for about four weeks after you do this laser therapy,” said Dr. Eric Leuthardt, a professor of neurosurgery at Washington University in St. Louis. “So not only are you killing the tumor, you are actually opening up a window of opportunity to deliver various drugs and chemicals and therapies that could otherwise not get there.”