Lung cancer screenings reduce risk of dying by 20%: Study

By Dr. Ananya Mandal, MDJun 30 2011

A lnew study shows some smokers' lives could be saved by screening with lung scans and the chances improve further if there is a false alarm.

It was noted that of those who got the recommended annual scans for three years, 4 out of 10 had a suspicious finding on at least one scan and were advised to have a follow-up test or biopsy. And more than 95 percent of them turned out to have nothing wrong. The results out Wednesday give the first detailed look at the benefits and risks of screening long time current or former smokers with special X-rays called CT scans. The government stopped the study last fall after seeing the scans were saving lives. However most insurers do not cover the scans and that is because no major groups currently recommend them. Dr. Christine Berg of the National Cancer Institute, the study's main sponsor said, “No one should rush off and get one of these scans for screening until we've thought more about it.”

For the study the researchers tested CT scans versus ordinary chest X-rays in 53,454 people over 55 with more than 30 pack-years of smoking: a pack a day for 30 years or two packs for 15 years. The study used top medical centers around the nation and low-radiation-dose machines. It involved skilled doctors who did less invasive tests in place of many biopsies and had far lower death rates when they did operate for lung cancer than is usual. The lower risk of death among those screened with scans in the study reflects all these things.

Each person would need three scans, one each year to show the benefit found in the study. No one knows if a single scan or testing less often would help. The reduction in the risk of dying from lung cancer among those given CT scans (356 deaths versus 443 in the X-ray group) was 20%. The reduction in the risk of dying from any cause during the study (1,877 deaths in the CT group versus 2,000 in X-ray group) was 7%.

A total of 320 people would have to be scanned for three years to prevent a single death from lung cancer. That's impressive when compared to the 1,339 women in their 50s who would need to have mammograms for several years to avoid one breast cancer death. However, mammograms are cheaper and involve less radiation so the risks and benefits aren't quite the same. The odds of dying from surgery for lung cancer were 1% among those in the study. In general practice, it's 4 percent. The average range of charges for a scan was $300 to $1,200. At some private practices it's up to $2,500.

Once the study results are analyzed for implications the guidelines may change say experts and these may help the nation's 94 million current and former smokers decide whether to be screened. Dr. Harold Sox, a Dartmouth professor who used to head the government task force that shapes policy on screening tests, said, “The question has changed to how are we going to do this.” He was writing an editorial with the results, published online Wednesday by the New England Journal of Medicine.

Dr. Otis Brawley, chief medical officer of the American Cancer Society said, “This is what happens when people get screened in the best of centers. When people start getting screened anyplace … the results may not be, and are likely not to be, as good.” He added, “People should not take this positive study as 'now it is safe to smoke’… because it isn't, and quitting remains the best way to lower cancer risk.”

Dr. Bruce Johnson, a lung cancer expert at the Dana-Farber Cancer Institute in Boston and a board member of the American Society of Clinical Oncology, doctors who treat the disease said of the screening, “Can society afford it? This comes with a substantial cost.”