Screening might avert many lung cancer deaths: study

A calculation based on results from a large lung cancer screening trial projects that 12,000 deaths a year among the highest-risk smokers and ex-smokers in the U.S. could be avoided with a national screening program.

The National Lung Screening Trial, published in 2010, found 20 percent fewer deaths from lung cancer in a group of people at highest risk for the disease when they were screened annually with CT scans, a form of high-resolution X-ray that can spot suspicious lung nodules.

Based on the 8.6 million Americans who would fall into that high-risk category because of a decades-long history of smoking, researchers at the American Cancer Society say in a new study that 12,000 fewer people a year would die of lung cancer if national screening were put in place.

"This is the first paper that attempts to assess the impact of screening on lung cancer cases nationally," one of the authors, Ahmedin Jemal, told Reuters Health. "Twelve thousand is a lot of cases," he said.

In the National Lung Screening Trial, current or former smokers between the ages of 55 and 74 who had accumulated 30 "pack-years" of smoking - for example by smoking 20 cigarettes a day for 30 years, or 40 cigarettes a day for 15 years - were considered to be at the highest risk for lung cancer.

The 20 percent reduction in deaths among people in that category in the trial was "a singular, enormous accomplishment" said Larry Kessler, of the University of Washington in Seattle, who studies the diagnostic value of screening technologies.

"That was a pivotal event that should have woken people up," said Kessler, who also wrote an editorial accompanying the new study in the journal Cancer.

To put a number on the potential benefits demonstrated in the NLST, the American Cancer Society researchers used U.S. census and health survey data to calculate the number of Americans at highest risk for lung cancer.

About 60,000 of those people die from lung cancer every year, according to their estimates, which could be reduced to 48,000 if every one of those people had a CT scan to identify early-stage nodules that could be removed surgically.

A national screening program would represent a breakthrough in the battle against lung cancer, which kills about 160,000 people in the U.S. every year, the researchers argue. Other major killers like breast cancer and colon cancer can be screened for with mammograms and colonoscopies, but lung cancers are too often caught too late for life-saving treatment, they point out.

Although the prospect of reducing deaths by 20 percent sounds significant, there's a reason screening hasn't been adopted since the NLST results came out two years ago, cautions Paul Pinsky, of the Division of Cancer Prevention at the National Institutes of Health in Bethesda, Maryland.

"You could do a quick back of the envelope calculation and come up with something pretty close to this," said Pinsky, who was not involved in the new study. "At most it's a rough ballpark of the potential effect if CT screening were introduced in a mass way."