An analysis of lung cancer incidence and screening found a decline in the proportion of patients with lung cancer meeting high-risk screening criteria, suggesting that an increasing number of patients with lung cancer would not have been candidates for screening, according to a study in JAMA (2015; doi:10.1001/jama.2015.413).
Lung cancer screening using low-dose computed tomography is recommended for high-risk persons by professional associations, including the US Preventive Services Task Force (USPSTF). Ping Yang MD, PhD, of the Mayo Clinic in Rochester, Minnesota, and colleagues conducted a study to examine the trends in the proportion of patients with lung cancer meeting the USPSTF screening criteria.
The study population included all Olmsted County, Minnesota, residents older than 20 years from 1984 through 2011, comprising approximately 140,000 people, of whom 83% were non-Hispanic white and socioeconomically similar to the general Midwestern US population. All pathologically confirmed incident cases of primary lung cancer were identified using the Rochester Epidemiology Project database.
Trends in lung cancer incidence rates were determined based on census data adjusted for the age and sex distribution of the US population in 2000. The proportion of cases meeting USPSTF screening criteria was identified. The criteria included asymptomatic adults 55 to 80 years of age, having a 30 pack-year smoking history, and currently smoking or having quit within the past 15 years.
There were 1,351 patients with a new diagnosis of primary lung cancer between 1984 and 2011. The proportion of patients with lung cancer who smoked more than 30 pack-years declined, and the proportion of former smokers, especially those who quit smoking more than 15 years ago, increased.
The researchers found there was a decline in the relative proportion of patients with lung cancer meeting the USPSTF criteria overall, from 57% in 1984-1990 to 43% in 2005-2011. The proportion of patients who would have been eligible under the criteria decreased among women from 52% to 37%, and from 60% to 50% among men.
“Our findings may reflect a temporal change in smoking patterns in which the proportion of adults with a 30 pack-year smoking history and having quit within 15 years declined,” the authors wrote.
“The decline in the proportion of patients meeting USPSTF high-risk criteria indicates that an increasing number of patients with lung cancer would not have been candidates for screening. More sensitive screening criteria may need to be identified while balancing the potential harm from computed tomography.”
This study was supported by grants from the National Institutes of Health, a grant from the National Institute on Aging, and funding from the Mayo Clinic Foundation.