Scientists Propose Adding Lasers to Brain Cancer Treatment

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Medicine can sometimes be counterintuitive. For example: A team of researchers now say that a little bit of laser-based brain damage may help people with cancer in the long run. They published their findings last week in the journal PLOS ONE.

There are many types of brain tumors. Glioblastomas are a type of malignant brain tumor that is both common and aggressive. Today, most patients diagnosed with glioblastomas will only live another 12 to 15 months. There are chemotherapy drugs that should help, but there’s also an obstacle: the blood-brain barrier, or BBB. The BBB is a defense system that prevents chemicals in the blood from accessing the brain. Ordinarily, this is a good thing, but when a tumor is in the brain, the BBB keeps these drugs out.

Last year, scientists penetrated the blood-brain barrier for the first time using focused ultrasound waves. That technique is still being developed but may one day lead to treatments for an array of illnesses.

Another treatment approach is called laser ablation. In this procedure, surgeons zap the brain tumor with a laser. The heat created by the laser kills the tumor, but it also damages surrounding cells, some of which belong to the BBB. The hole in the BBB created by the laser can take four to six weeks to heal. In that time, scientists realized, they might be able to essentially sneak drugs past the barrier into a patient’s brain.

To find out, the researchers performed laser ablation on 14 patients with glioblastomas and treated the patients with a chemotherapy drug called doxorubicin. They scanned the patients’ brains before and after the procedure to monitor the permeability of the blood-brain barrier. They also measured levels of a chemical called brain-specific enolase, which is another indicator of damage to the BBB.

The lasers did the trick. Immediately after laser ablation and for up to six weeks afterward, the patients’ BBBs dropped their guard enough to allow the drug to cross into the brain. The researchers say that this six-week period could be a perfect window in which to administer chemotherapy.

"The hope is that we can help patients live longer,” co-lead author David D. Tran said in a press statement.

With only 14 patients, this study was small, but the researchers believe their findings are still significant. They will continue to study the idea and intend to integrate laser ablation into future cancer drug trials.