The human brain has a extraordianry defense system that filters bacteria and chemicals. For brain tumor patients, the boundary works almost too well by blocking most chemotherapy drugs.
Now, a team led by a University of Florida Health researcher has found that a laser system already used to kill brain tumors has another benefit: It opens a temporary “window” in the blood-brain barrier that enables crucial chemotherapy drugs to pass into the brain for up to six weeks.
The discovery raises the possibility that a host of chemotherapy drugs once rendered ineffective by the blood-brain barrier could now be used against glioblastoma, said David D. Tran, M.D., Ph.D., chief of neuro-oncology in the UF College of Medicine’s department of neurosurgery and co-lead author of the study.
Glioblastoma is the most common and deadliest malignant brain tumor in adults. There is no effective long-term treatment and patients usually live for 12 to15 months after diagnosis, according to the National Cancer Institute.
“The hope is that we can help patients live longer. We know that there are several drugs out there that should work on brain tumors,” Tran said.
The research was carried out at the Washington University School of Medicine in St. Louis, where Tran collaborated with a group that included neurological surgery professor Eric C. Leuthardt, M.D., and Joshua S. Shimony, M.D., Ph.D., an associate professor of radiology.
The findings show for the first time that the blood-brain barrier can be temporarily disrupted at tumor sites, Tran said. That provides a precise location and a longer “window of opportunity” for chemotherapy drugs to enter the tumor and take effect, he said.
In a pilot trial, 14 brain tumor patients underwent laser ablation and were treated with doxorubicin, a chemotherapy drug that is normally blocked by the blood-brain barrier. Preliminary data suggest there could be a survival benefit to giving chemotherapy during the four- to six-week opening in the blood-brain barrier, Tran said.
While it was a small number of study subjects, Tran said the results are sufficient to show that laser ablation creates the crucial opening in the blood-brain barrier. The initial findings are part of a larger, ongoing clinical trial involving 40 patients.
“This gives us a very significant window of time to give chemotherapy,” Tran said. “We will be able to test a lot of drugs for effectiveness.”