March 18, 2003 -- Smoking is the most common cause of lung cancer, but not all smokers face the same risk of developing the disease. Researchers say lung cancer risk varies widely among current and former smokers, and a new tool may help predict a person's 10 year risk level and determine when lung cancer screening is necessary.
Researchers say many smokers are now opting for lung cancer screening using computed tomography (CT) scans in hopes of catching the disease early and improving their chances of successful treatment -- even though there's no proven benefit associated with these lung cancer screening programs. In fact, these CT scans often do more harm than good by producing a high number of false-positive results.
But by looking at a person's age, sex, and smoking history, researchers say they've developed a risk assessment tool that can accurately estimate a person's risk of developing lung cancer within the next 10 years.
"The risk assessment tool should help physicians and patients balance the possible risks and benefits of screening," says researcher Peter Bach, MD, of Memorial Sloan-Kettering Cancer Center in New York City, in a news release.
"For example, the subjects in our study who were at the low end of risk had less than a 1% chance of getting lung cancer in the next ten years. That needs to be contrasted with the 30 to 50 percent risk that a screening CT will show some lung scare or shadow that requires further evaluation or surgical therapy, even though it will ultimately be deemed harmless," says Bach.
The study, which appears in the March 19 issue of the Journal of the National Cancer Institute, analyzed data gathered from 18,172 current and former smokers who participated in a previous lung cancer prevention study.
For example, a 51-year-old woman who smoked one pack per day for 28 years before quitting nine years earlier had a less than 1% chance of developing lung cancer in the next 10 years. But a 68-year-old man who has smoked two packs a day for 50 years and was still a smoker has a one in seven chance (15%) of getting lung cancer in the next decade.
Researchers say that with more than 90 million current and former smokers in the U.S., the tool should provide a valuable method for doctors to identify those most at risk of lung cancer due to smoking who might have the most to gain from lung cancer screening.