Surgeons use florescent light to target brain cancer

October 5, 2010 7:27:46 PM PDT
An experimental technique is giving Bay Area surgeons a way to attack brain tumors with more precision than ever before and the advantage is clearly visible.

After earlier treatments, one patent had his brain cancer come back three times, but this time director of neurosurgery at UCSF Dr. Mitchel Berger believes the odds are better.

"The overall goal here is to give a substance to a patient to illuminate a tumor, so we can take it out in a more aggressive fashion," says Berger.

The tumor itself is clearly visible on the operating room monitors, but when the lights are turned off, Berger can get any entirely different view of it.

A blue light shining down from the microscope is part of an experimental technology. Several hours before the operation, the patient was given an oral dose of an organic dye known as 5-ALA. The substance migrates into tumor cells, causing a biological reaction that turns them fluorescent, making them clearly visible under the laser light.

"This is a glowing tumor now. The dye is being excited and it's turning the tumor orange," says Berger.

Using the microscope to guide him, Berger's instruments zero in on the highlighted orange areas to remove the tumor itself.

"This is like flying a plane with radar at night," says Berger.

But he says the real advantage will come next, when he begins hunting for cancer that often remains hidden.

"Because a lot of times the tumor is very clear, but the actual infiltrating margin looks just like normal brain. So it's hard to find those cells. But now that they're orange, we can go after them selectively," says Berger.

For an hour, Berger methodically clears out the tiny spots of orange, eliminating cells that could cause the tumor to return.

"So not only have we taken out the tumor, but we've taken out any of the small cells," says Berger.

The fluorescence-guided glioma surgery is new in the U.S. and Berger's team is leading a clinical trial. But there are results from a study in Europe showing long-term benefits for patients.

In that study, published in the journal The Lancet, a German research team found that surgeons were nearly twice as successful at removing the entire tumor using the fluorescent technique and after six months, those patients were twice as likely to have no recurrence.

With all the visual evidence of cancer cleared away, the patient is ready for post operative cancer treatments, which Berger's team believes have my higher chance of success.

"Absolutely, this told us we not only took out the tumor, but we took out invading, infiltrating tumor margin, which is really going to make a huge impact for him in terms of his outcome," says Berger.

This procedure was the first ever performed in the U.S., but Berger believes the clinical trial could lead to mainstream use of the fluorescent dye technique within one to two years.


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