New Radiation Therapy May Aid Cancer Battle

INDIANAPOLIS — When doctors diagnosed Billy Stamm with lung cancer, there was more bad news to come. Not only was surgery out of the question, the odds weren’t good that he would respond to conventional radiation therapy.

Stamm’s frail lungs were so ravaged by years of emphysema, bronchitis and a two-pack-a-day cigarette habit that radiation therapy to kill the tumor also would have injured healthy tissue.

But the service station worker wasn’t without hope. One of his doctors told him about an experimental therapy being tested at the Indiana University School of Medicine. It used precisely aimed high doses of radiation to try to kill tumors while sparing healthy tissue.

Stamm’s doctors said there was a chance the tumor in his right lung wouldn’t spread if he chose no treatment. But he decided to give the new therapy a shot.

“I said, ‘I’m game for just about anything right about now,’ ” said Stamm, 57, who was diagnosed in November.

In June, Stamm became the seventh patient with inoperable lung cancer to receive the new treatment--stereotactic body radiotherapy--as part of a clinical trial at the Indianapolis school.

The first tests of the new therapy are aimed only at determining the highest radiation level that can safely be given to the 35 or so patients expected to participate.

But the hope is that it will lead to a second clinical trial that will reveal it as a potent treatment for inoperable, early-stage lung cancer, according to Dr. Mark Williams, the trial’s principal investigator.

“We’re hoping this can become another option for a patient group that has few options,” said Williams, a clinical assistant professor at the university.

For lung cancer patients whose disease is in the early stage, the gap in survival prospects between those who undergo surgery to remove tumors and those who can’t is stark.

Patients who undergo surgery have a cure rate between 50% and 70%. But for patients with inoperable tumors who get conventional radiation instead, the cure rate is only 20% to 30%.

Considering those numbers, a more effective radiation therapy would be an important development, said Dr. Robert D. Timmerman, assistant professor of radiation oncology at the medical school.

Since the therapy was first used to treat a patient in the United States, at Indiana University in 1997, it has extended the predicted life spans of liver, colon and breast cancer patients whose cancer had spread, he said.

Timmerman, the trial’s co-principal investigator, anticipates improved results in clinical trials because its subjects have lung cancer that hasn’t spread to other organs.

The new therapy taps into several advanced technologies, including 3-D imaging, radiation beams that can be tailored to the shape of the tumor and a new way to hold patients virtually motionless to target the cancer.

A similar approach is used to target brain tumors. But it wasn’t easy to transfer that technology beyond the cranium’s fixed tissues because tissue in the body’s torso tends to shift, Timmerman said.

The new therapy solves that problem with a special body frame designed in Sweden to hold patients extremely still. The patient lies on a Styrofoam body pillow that, when the air inside it is vacuumed out, creates a mold of the patient. The pillow is saved and used in subsequent treatments to place the patient in the same position.

A device Timmerman likens to an apple press is pressed against the patient’s chest to restrict breathing as minute adjustments are made to the body frame before photon radiation is fired at the cancer.

Because positioning each patient for treatments can take up to an hour, some need sedatives to remain still, Timmerman said.

But the long wait is worth it because the cancer can be precisely targeted, he said.

Conventional radiation therapy can only be focused at areas with diameters of 1.2 to 1.5 inches--threatening healthy tissue--the new therapy can hit targets two-tenths of an inch in diameter.

That accuracy is possible with technology similar to that used to target missiles. During an MRI or CAT scan, coordinates are assigned throughout the patient’s body to create a grid system that allows a tumor’s location to be known precisely when the patient is in a specific position.

Once the tumor is in the cross hairs, it is blasted with radiation from seven directions.

And while patients in conventional radiation therapy receive about 35 separate treatments over a six-week period, the new treatment requires three treatments over about a 10-day period.