What is the role of Computed Tomography (CT) for lung cancer screening?

From the Guidelines

CT screening for lung cancer is recommended annually for high-risk individuals aged 55-80 who have a 30 pack-year smoking history and currently smoke or have quit within the past 15 years, using low-dose computed tomography (LDCT) to reduce lung cancer-related mortality by 20%. This recommendation is based on the findings of the National Lung Screening Trial, as reported in the Annals of Oncology 1. The screening approach has been shown to be effective in detecting small lung nodules that might represent early-stage cancer, thereby reducing lung cancer mortality in high-risk populations.

Key Considerations for Screening

• The screening should be limited to individuals at high risk of death from lung cancer, as stated in the American Journal of Respiratory and Critical Care Medicine 1.
• Patients should have a shared decision-making discussion with their healthcare provider about benefits, potential harms (including false positives, incidental findings, and radiation exposure), and smoking cessation if applicable.
• Insurance coverage, including Medicare, typically covers this screening for eligible individuals, as mentioned in the Journal of the National Comprehensive Cancer Network 1.
• Screening should be discontinued once a person has not smoked for 15 years or develops a health problem significantly limiting life expectancy or ability to undergo curative lung surgery.

Implementation of Screening

The implementation of LDCT screening should consider the potential benefits of screening (reduced mortality from lung cancer) and possible harms, as discussed in the American Journal of Respiratory and Critical Care Medicine 1. A comprehensive understanding of these aspects of screening will inform appropriate implementation, with the objective that an evidence-based and systematic approach to screening will help to reduce the enormous mortality burden of lung cancer. The complete version of the NCCN Guidelines for Lung Cancer Screening provides recommendations for initial and subsequent LDCT screening and provides more detail about LDCT screening, as reported in the Journal of the National Comprehensive Cancer Network 1.

From the Research

Lung Cancer Screening with CT

• Lung cancer is the second most common cancer and the leading cause of cancer death in the US, with a 5-year survival rate of 20.5% 2.
• The US Preventive Services Task Force (USPSTF) recommends annual screening for lung cancer with low-dose computed tomography (LDCT) in adults aged 50 to 80 years who have a 20 pack-year smoking history and currently smoke or have quit within the past 15 years 2.
• LDCT screening has been shown to significantly reduce lung cancer mortality in high-risk populations, with a 20% overall reduction in lung cancer mortality compared to chest X-ray 3.
• Early lung cancer detection leads to better survival outcomes, with patients diagnosed with stage 1A lung cancer having a >75% 5-year survival rate, compared to <5% at stage 4 3.

Benefits and Harms of Screening

• The benefits of LDCT screening include a reduction in lung cancer mortality and improved survival outcomes 3, 4.
• The harms of LDCT screening include false-positive results, overdiagnosis, radiation exposure, and costs 4, 5.
• The USPSTF concludes with moderate certainty that annual screening for lung cancer with LDCT has a moderate net benefit in persons at high risk of lung cancer based on age, total cumulative exposure to tobacco smoke, and years since quitting smoking 2.

Implementation of Screening Programs

• Successful implementation of LDCT lung cancer screening is dependent on many factors, including population selection, recruitment strategy, computed tomography screening frequency, lung-nodule management, participant compliance, and cost effectiveness 3.
• Evidence shows that through the appropriate use of risk-prediction models and a more personalized approach to screening, efficacy could be improved 3.
• Extending the screening interval for low-risk individuals to reduce costs and associated harms is a possibility, and through the use of volumetric-based measurement and follow-up, false positive results can be greatly reduced 3.