For smokers and former smokers, the threat of lung cancer always lurks in the shadows. To screen, some decide to get their lungs scanned by a CT machine, which can find a tumor early enough to stop it or set off a false alarm that turns out to be nothing.

Others might avoid the sans, or don't know they should have one, even though they are the type of person who has the most to gain from screening, according to official recommendations in effect for the last five years.

Now, a new study shows how to personalize the lung cancer screening decision for every patient. The results could help doctors fine-tune their advice to patients so that it's based not just on a patient's lung cancer risk and the potential benefits and harms of screening, but also a likely range of patient attitudes about looking for problems and dealing with the consequences.

The tool for clinicians, called Lung Decision Precision, was designed by a University of Michigan and Veterans Affairs team to help clinicians talk with patients and their loved ones about whether to a lung CT scan might be a good idea for them.

The same team has also launched a website for patients and their loved ones, http://www.shouldiscreen.com, that gives easy-to-understand information about the positives and potential negatives of lung cancer screening, and allows individuals to calculate their risk of lung cancer.

Tanner Caverly, M.D., M.P.H., led the team that did the new computer-based simulation analysis using data from major studies of lung cancer screening, and national data on the potential screening population under the current guidelines.

"Our model is built on a comprehensive view of net benefits for individual patients, which incorporates the best evidence for personalizing the pros and cons of screening and assumes that not all patients will feel the same about screening and its consequences," explains Caverly, an assistant professor in the Division of General Medicine and Department of Learning Health Sciences at the U-M Medical School. 

Any person with an annual chance of lung cancer between 0.3% and 1.3%, and a life expectancy of more than 10 years falls into that latter high-benefit category, he notes. This accounts for about 50% of all Americans who qualify for screening under the current guidelines.

In fact, for them, personal preference is more important to their decision than the false-positive rate for lung CT screening (which outnumber true cancers 25 to 1), and the negative impacts of being over-treated for lung cancer that was not highly dangerous.

Looking at lungs

The researchers focused on lung cancer the leading cause of cancer death among both men and women because of the recent move to encourage certain smokers and former smokers between the ages of 55 and 80 to get screened for it.

A major study published in 2011 showed that some members of this group could survive longer if they had CT screening to find the earliest signs of lung cancer, which is diagnosed in more than 230,000 Americans every year.