By Jenifer Goodwin HealthDay Reporter THURSDAY, June 30 (HealthDay News) -- Annual low-dose CT scans cut the death rate from lung cancer by 20% in heavy smokers and formerly heavy smokers, compared to those who get annual chest X-rays, according to the results of a major National Cancer Institute study released on Wednesday. Experts are calling the findings a major advance in efforts to combat lung cancer deaths. By catching the cancer early, the tumors can be removed surgically -- hopefully before they've spread and become very difficult to cure. "This is a momentous time in the history of public health research," said Dr. Otis Brawley, chief medical officer of the American Cancer Society. "The NLST [National Lung Screening Trial] is the best-designed and best-performed lung cancer screening study in history." Yet the findings raise as many questions as they answer, said Dr. Harold Sox, a professor emeritus of medicine at Dartmouth Medical School who wrote an