Posted on January 02, 2018
A study from the National Cancer Institute (NCI) offers new evidence that individualized lung cancer risk-based screening may be more effective at preventing lung cancer deaths than current U.S. Preventive Services Task Force (USPSTF) screening criteria.
The USPSTF recommends annual low-dose computed tomography (CT) screening for individuals aged 55 to 80 who have a history of heavy smoking (at least one pack of cigarettes per day for 30 years or more) and who currently smoke or have quit within the last 15 years. However, these criteria may exclude some smokers who would be considered at high risk for lung cancer based on individual risk estimates that more specifically account for demographic, clinical, and smoking behaviors1.
A previous analysis showed that the USPSTF criteria identified fewer ever-smokers for lung cancer screening in 2015, compared to 2010. Li Cheung, Ph.D., and colleagues decided to investigate the reasons fewer individuals were assigned to screening, and to determine the impact of that shift on lung cancer death. In addition, they examined whether a validated risk-based model using fixed risk thresholds would have similar declines in the number of ever-smokers eligible for screening and the number of lung cancer deaths prevented.
The investigators report that, due to changing smoking behaviors in the U.S. population between 2010 and 2015, the use of USPSTF criteria could result in the identification of 1.5 million fewer ever-smokers eligible for CT screening and 8,000 fewer lung cancer deaths averted in 2015 compared to 2010. When investigators evaluated the ever-smoker population using individual risk-based criteria, they found more modest declines in the numbers screened and deaths averted in 2015 compared to 2010.
This gap in screening effectiveness between risk-based and USPSTF screening criteria has widened substantially in recent years and may continue to expand as smoking prevalence and intensity decrease among young people in the U.S. To better capture high-risk smokers and prevent premature deaths from lung cancer, eligibility for screening should be based on a risk threshold that balances benefits, costs, and harms.
Reference: Cheung et al. Preventing Lung Cancer Mortality by Computed Tomography Screening: The Effect of Risk-Based Versus U.S. Preventive Services Task Force Eligibility Criteria, 2005–2015. Ann. Int. Med. January 2, 2018. DOI: 10.7326/M17-2067
1The individual risk model is based on age; education; sex; race; smoking intensity, duration, and quit-years; body mass index; family history of lung cancer; and self-reported emphysema.