International Non-small Cell Lung Cancer Collaborative Group researchers looked at 1,200 patients from six trials and found the five-year survival rate was 10.8 percent with sequential therapy and 15.1 percent with concurrent therapy.

Research team leader Dr. Walter Curran Jr., of Philadelphia's Radiation Therapy Oncology Group, a cooperative clinical trials organization, said the only difference is in the timing of the two treatments. Giving the radiation treatment on day one instead of day 40 could increase the number of five-year-survivors in 50,000 patients from 5,000 to 7,500, Curran said.

"That means a relative increase of nearly 50 percent," Curran said in a statement. "We've demonstrated that the magnitude of benefit is observable in many studies, regardless of the regimen. I think it will be as persuasive as any data that this will change not only the tumor control rate but the chance for a long-term cure."

Curran presented the results in Los Angeles at the meeting of the American Society for Therapeutic Radiology and Oncology.