From the Guidelines
The risk of lung cancer for a 72-year-old with a 20 pack-year smoking history who quit 10 years ago remains significantly elevated, approximately 3-4 times higher than a never-smoker's risk, despite a substantial decrease in risk since quitting. According to the NCCN Guidelines 1, individuals who previously smoked have a substantially higher risk of lung cancer compared with those who have never smoked, and there is no substantive drop off in that risk after 15 years since quitting. A study analyzing the Framingham Heart Study found that lung cancer risk remains more than 3-fold higher in individuals who previously smoked after 25 years since quitting than in those who had never smoked 1. Given your age and smoking history, you should discuss lung cancer screening with your doctor, as you likely qualify for annual low-dose CT scans under current guidelines 1. These screenings can detect lung cancer at earlier, more treatable stages. Additionally, maintaining a healthy lifestyle with regular exercise, a diet rich in fruits and vegetables, and avoiding secondhand smoke can further help reduce your overall cancer risk. Some key points to consider include:
- The USPSTF has a grade B recommendation for lung cancer screening with LDCT for individuals at high risk, which includes those aged 50 to 80 years with a cigarette smoking history of ≥20 pack-years 1.
- The NCCN Guidelines differ from the USPSTF and CMS national coverage recommendations by not including time since quitting smoking as an eligibility criterion for lung cancer screening 1.
- An estimated 15 million individuals in the United States meet the criteria for lung cancer screening 1. It is essential to note that while quitting smoking has significantly reduced your risk, it is crucial to continue monitoring and maintaining a healthy lifestyle to minimize your risk of lung cancer 1.
From the Research
Lung Cancer Risk Factors
- Age is a significant risk factor for lung cancer, with increasing age associated with a higher risk of developing the disease 2
- Smoking history is also a crucial risk factor, with a 20 pack-year history of smoking significantly increasing the risk of lung cancer 2, 3, 4, 5
Screening Recommendations
- 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, 5
- Screening should be discontinued once a person has not smoked for 15 years or develops a health problem that substantially limits life expectancy or the ability or willingness to have curative lung surgery 2
Risk of Lung Cancer in Former Smokers
- A study found that former smokers with 20 or more pack-years of smoking who quit 15 or more years ago still have a high risk of lung cancer, with a cause-specific hazard ratio (HR) of 11.19 (95% CI, 5.40-23.21) compared to never smokers 4
- Another study found that LDCT screening can reduce lung cancer-related mortality by 21% in high-risk populations, including former smokers 6
Individual Risk Assessment
- For a 72-year-old individual with a 20 pack-year history of smoking who quit 10 years ago, the risk of lung cancer is still significant, although the USPSTF does not recommend annual screening for individuals who have quit smoking for more than 15 years 2, 4
- However, the individual's risk factors, including age and smoking history, should be taken into account when assessing their risk of lung cancer 2, 4