As the number of smokers in the U.S. has been declining as a result of public health efforts, so too has the number of new cases of lung cancer.
In men, the death rate from lung cancer has been declining since the late 1990s, and it is starting to decline for women.
"Smoking rates started to fall in men about 30 years ago, and in women 20 years ago, and that is now being manifested by falling rates in the number of lung cancers and in the number of people dying from lung cancer," Johnson said.
Screening for lung cancer has been somewhat controversial. A large trial -- the National Lung Screening Trial -- should be reporting results in about a year, to help researchers make a more definitive conclusion about whether screening has benefit in patients at risk for lung cancer.
Some are already proponents of screening.
"That would be a big help if we had an effective screen," Johnson said. "Cancers that have seen a rather dramatic decline in deaths are prostate, breast, and colon -- and there are screens for all of those."
Others, however, are not so certain the screening will have similar success in a more aggressive cancer.
"It's not the quantity of tumor, it's the quality of tumor," said Dr. Roy Herbst, a thoracic oncologist at M.D. Anderson Cancer Center in Houston. "All it takes is a couple cells that spread to the brain, liver, or bone. Even if you cut that tumor out early, that patient still might end up with recurrent disease very soon."
He feels that "ultimately, screening will be very important," but not until researchers can molecularly characterize the tumor and, therefore, "understand what markers will put that patient at risk or not."
Rudin hopes the trial will answer the most important question, of whether screening actually alters lung cancer mortality: "That's a much higher hurdle to prove."