The guidelines, published online in the Journal of Thoracic and Cardiovascular Surgery, call for low-dose CT (LDCT) screening of smokers and former smokers ages 55 to 79 years who have a smoking history of at least 30 pack-years, as well as screening of long-term lung cancer survivors in the same age range.
In contrast to the more restrictive ACCP guidelines published online May 20 in the Journal of the American Medical Association, the AATS recommendations also include individuals with a smoking history of as few as 20 pack-years -- as long as the screening subjects have an additional risk factor for the disease, such as a family history of lung cancer.
"The task force strongly encourages the use of risk calculators to assist in creating a more quantified approach to this extension," wrote lead author Dr. Francine Jacobson, from Brigham and Women's Hospital, and colleagues (J Thorac Cardiovasc Surg, June 20, 2012).
"Beginning annual lung cancer screening with LDCT for smokers and former smokers at age 50 years with a 20 pack-year history of smoking should be considered when the additional comorbidity produces a cumulative risk of developing lung cancer of 5% or more over the following five years," the authors wrote. Screening of a woman may be deferred before menopause, they noted.
In another divergence from last month's guidelines, the AATS group found no evidence in the literature to limit lung cancer screening of high-risk individuals to three years, and the guidelines recommend that screening continue through age 79 for those at risk.
AATS' multidisciplinary Lung Cancer Screening and Surveillance Task Force included four thoracic surgeons, four thoracic radiologists, four medical oncologists, one pulmonologist, one pathologist, and one epidemiologist.
The group examined the available literature, including lung cancer screening trials in the U.S. and Europe, and discussed local best clinical practices in the U.S. and Canada in conference calls, working with the support of a reference librarian who assisted with interdisciplinary evidence.
For clinical practices in the U.S. and Canada, the task force unanimously recommended annual lung cancer screening and surveillance with low-dose CT, as follows:
- Screening is recommended for smokers and former smokers with a 30 pack-year history of smoking and long-term lung cancer survivors ages 55 to 79 years.
- Screening may begin at age 50 years with a 20 pack-year history of smoking and additional comorbidity that produces a cumulative risk of developing lung cancer of 5% or greater over the following five years.
- Screening should be undertaken with a subspecialty qualified interdisciplinary team.
- Patient risk calculator application and intersociety engagement will provide data needed to refine future lung cancer screening guidelines.
In a nod to dose-reduction efforts aimed at mitigating any harm from the CT scans, the authors noted that "reducing the radiation dose for CT scanning has become a central focus for scanner manufacturers and radiologists. It is likely that in the near future, new methods of reconstructing the images will provide significantly lower doses than even the 1.5 total body equivalent dose estimates for [the National Lung Screening Trial (NLST)]."
As for cost-effectiveness, the group cited a recent report in Health Affairs estimating the cost per life-year saved at a low $19,000 per year. "This compares favorably to cost per life-year saved in breast ($31,000-$52,000), colon ($19,000-$29,000), and cervical cancers ($50,000-$75,000)," the authors wrote. Other cost estimates have been much higher.
The report also cited the NLST's finding of a 7% decrease in all-cause mortality in addition to the 20% reduction in lung cancer mortality as a hopeful sign of CT's ability to detect serious disease that may be asymptomatic.
"LDCT provides additional valuable information regarding health and disease processes, including diffuse lung diseases and cardiovascular disease," they wrote. "Emphysema, identified by screening, is an independent risk factor for the development of lung cancer."
Going forward, genetics is also expected to provide answers as to "why particular patients develop lung cancer while others with the same smoking history do not," Jacobson and colleagues wrote. "In the future, this may lead to differences in recommendations for screening based on individualized risk."
New data will continue to update the view of professionals who are engaged in the dialog of how best to detect lung cancer in the coming months and years, they wrote.
"The issues that direct public health and societal allocation of resources will be important, but we have entered a new era for the early detection of lung cancer," the group concluded.