WEDNESDAY, Nov. 4 (HealthDay News) -- Three-year survival was 100 percent for people with early-stage lung cancer and good lung function who were treated with radical stereotactic radiosurgery using CyberKnife, according to a new study funded by the product's maker.

Standard care for people with small lung tumors calls for surgical removal of the affected lobe, but some people cannot have surgery because of other medical conditions, such as heart disease or emphysema.

"Our goal has been to find a reasonable option for patients who don't want or can't tolerate surgery," the study's lead author, Dr. Brian T. Collins, a radiation oncologist at the Lombardi Comprehensive Cancer Center at Georgetown University Hospital, said in a news release from the university. "What we discovered is a very promising option that may be relevant for other stage 1 patients as well. More follow-up with these patients is planned to see how they progress five years after treatment."

Stereotactic radiosurgery, despite its name, is not surgery but rather a type of radiation therapy that focuses high-powered X-rays on abnormal tissue only, sparing nearby healthy tissue.

The study included 24 people with early-stage lung cancer. Three years after undergoing stereotactic radiosurgery, overall survival was 79 percent. Five deaths were attributed to progressive lung dysfunction. But among those with better lung function, survival was 100 percent, the researchers reported. The treatment was found to be well tolerated, with most people reporting only mild fatigue.

"What we also learned from this study is that patients with poorer lung functioning don't do nearly as well," Collins stated in the news release. The overall survival in this group of patients was only 30 percent, the researchers found.

"This information is important for the doctor and patient when making treatment decisions. In treating someone with poor lung function, it would seem prudent to modify the treatment dose in order to reduce further damage to the lungs that stereotactic radiosurgery causes," Collins added.

The study was scheduled to be presented Nov. 3 at the American Society of Chest Physicians annual meeting in San Diego. It was funded by the CyberKnife Society, a nonprofit group supported by Accuray, which makes CyberKnife systems. Collins has been a paid clinical consultant for Accuray.

More information

The Radiological Society of North America has more about stereotactic radiosurgery.