It has been known for years that smoking causes most lung cancer - after it causes the cancer, smoking blocks your body from fighting it. According to the Centers for Disease Control and Prevention (CDC), nearly nine out of ten men who die from lung cancer are smokers.
Portland is one of eight VA facilities chosen to develop a comprehensive a lung cancer screening system so we can provide high-quality care to high-risk Veterans. In addition to determining how best to care for Portland area Veterans, we will provide information that will help determine the best practices for lung cancer screening that may be used throughout the U.S.
Among middle-aged smokers, lung cancer is the cause of 33 percent of overall mortality. Veterans have an even higher lung cancer incidence and mortality than the general population, and in 2007, almost 5,000 Veterans were treated for lung cancer in VA facilities.
Lung cancer does not usually cause noticeable symptoms until it has spread. Most patients are diagnosed after it has already spread so treatments are generally less effective than they could be. Accordingly, there is great interest within and outside VA to find ways to diagnose lung cancer earlier when treatments work better.
One method to diagnose lung cancer when treatments are more effective is to screen for it; that is, look for early lung cancers in people who are not having symptoms. Screening is what is commonly done for breast and prostate cancers.
Recent studies have evaluated whether computed tomography (CT or “cat”) scans help people at high risk of developing lung cancer, namely heavy smokers, to live longer. Under contract from the U.S. Preventive Services Task Force, the organization that helps primary care clinicians make decisions about screening, investigators at the Portland VA and Oregon Health & Science University reviewed thousands of studies that have addressed this topic.
The investigators reviewed over 8,000 papers related to the topic and narrowed that list to studies that directly addressed whether CT scans benefitted people at high risk of developing lung cancer. Four trials reported results of CT screening among patients who smoked: one large trial involving screening indicated mortality reductions of 20 percent and 7 percent, respectively. In other words, in a group of 1,000 people screened once a year for three years, three fewer people had died of lung cancer after 6 years; instead of 21 people, 18 people per 1,000 died of lung cancer. However, potential harms to patients included radiation exposure and a high rate of false positive examinations, which were typically resolved with further imaging.
In conclusion, moderate evidence shows that low dose CT screening can reduce lung cancer and all-cause mortality, but there are also harms associated with screening that must be balanced with the benefit. Screening has only been studied in people at high risk of developing lung cancer who are or have been heavy smokers. Screening people at lower risk of lung cancer will likely lead to many more harms than benefits. It is also important to note that the benefits of screening were shown in a study where comprehensive systems were in place to best care for patients before, during, and after the CT scan.
Based on the review of the evidence, the U.S. Preventive Services Task Force recently recommended that people who have been heavy smokers discuss lung cancer screening with their doctor (http://www.uspreventiveservicestaskforce.org/uspstf13/lungcan/lungcansumm.htm). The Task Force stresses that screening should only occur within health care systems that can optimally care for patients during the entire screening and treatment process. Because lung cancer screening of this type is new, these systems are just starting to be designed and tested. As they are validated, systems will be established throughout the VA health care system and details will be shared with Veterans about their care options.
We are very excited to see our research results lead to improved care. As a Veteran, if you have any questions or concerns related to smoking and your health, please speak to your primary care provider who will provide you guidance and care based on your particular situation.