A new study shows that CT scans can reduce the risk of death from lung cancer by 20 percent.

Until now, early detection of lung cancer was considered almost impossible. Often by the time a patient experienced symptoms, it is too late to cure them.

"We've been looking for over 40 years to try to find a way to reduce deaths from lung cancer with screening," Len Lichtenfeld, chief medical officer for the American Cancer Society, said.

This new study is the first to show clear evidence that CT scans significantly reduce lung cancer deaths.

"The feeling really is that I'm thrilled because all the work we have put in was to save lives," Dr. Claudia Henschke, with Mt. Sinai School of Medicine, said.

The American Cancer Society may now change its recommendations on cancer screening to include CT scans.