Lung cancer is the number one cancer killer, and so far there has not been an effective way to screen to find early cancers.
This study found that low-dose CT scans did save lives, however it may begin a new era in which patients who are former smokers need to be very careful so that when they try to protect themselves, they don't step into an unnecessary problem.
What we now know about the benefits of low-dose CT scanning for long time smokers is what is published in the study in tomorrow's New England Journal of Medicine.
Over 53,000 people were screened 3 times at one year intervals. Half of the people got screening with chest x-rays and the other half got low-dose CT scans.
5 to 7 years later, the results showed a benefit for those who got screened with the low-dose CT scans.
"It prevented about 1 in 5, about a 20% benefit," said Dr. Peter Bach of Memorial Sloan Kettering Cancer Centers.
Many hospitals around the country already have or are preparing screening programs.
But in this case, Dr. Bach says this is not a screening test meant for every former smoker, age and smoking history count.
This is because getting screened also carries some risks, and people should be well aware that the test itself can create some problems like extra testing, some radiation exposure and possibly unnecessary surgery.
The way to maximize the benefit and minimize the risk for now, according to many experts, is to offer scans only to people over age 55 who have smoked at least 30 years, just like the people in the study.
One local hospital is already offering scans to people over age 40, people who are not necessarily at a high risk.
Patients should be well informed about the potential risk and possible benefits before being signed up for screening. This is a case where the benefit can be huge, but so can the risk. There's even a small risk of death.
Insurance does not pay for the screenings, so a person opting to pay the many hundreds of dollars that the test costs, should make sure they're in the right subgroup for benefit, over age 55 and a smoker for some 30 years. Much still needs to be worked out from this new understanding of these screenings.