New lung cancer screening guidelines from the American Cancer Society (ACS) may significantly expand the volume of annual low-dose computed tomography (LDCT) exams performed for current and previous smokers and could significantly reduce lung cancer-related mortality.
In the new recommendations, recently published in CA: a Cancer Journal for Clinicians, the ACS emphasized expanding the age range for annual LDCT lung cancer screening (LCS) from the 2013 recommendation of 55 to 74 to 50 to 80 years of age for current and previous smokers. The ACS has also changed the smoking history criteria from > 30 pack-year history to > 20 pack-year history.
Among the randomized trials the researchers considered in assessing lung cancer screening recommendations was the 2020 NELSON trial, which examined LDCT screening in over 15,000 high-risk current and former smokers ranging between 50 to 74 years of age. For this trial, the minimum pack-year history was 15 to 18.75. The researchers noted that 10-year follow-up data from this trial revealed 33 percent and 24 percent relative reductions in lung cancer deaths in women and men respectively.
“The importance of the NELSON trial was the additional evidence supporting the efficacy of LCS with LDCT and the demonstration of a significant reduction in lung cancer mortality in a younger cohort that included individuals with a lighter smoking history,” noted Andrew M. Wolf, M.D., the lead author of the ACS guideline update and professor of internal medicine at the University of Virginia School of Medicine, and colleagues.
Another key change in the 2023 ACR recommendations involved smoking status. For previous smokers, the 2013 ACR guidelines emphasized annual LDCT screening for people who had quit smoking within the past 15 years. Based on the evidence, the ACR has eliminated the years since quitting smoking (YSQ) screening parameter for previous smokers.
Three Key Takeaways
- Expanded age range. The American Cancer Society (ACS) has recommended expanding the age range for annual low-dose computed tomography (LDCT) lung cancer screening from 50 to 80 years of age for current and previous smokers, compared to the previous recommendation of 55 to 74 years.
- Reduced pack-year smoking history threshold. The ACS has changed the smoking history criteria for eligibility from > 30 pack-year history to > 20 pack-year history, making more individuals eligible for screening.
- Elimination of years since quitting smoking (YSQ) parameter. The guidelines no longer consider the number of years since quitting smoking (YSQ) as an eligibility factor for previous smokers, which may lead to a greater than 20 percent reduction in lung cancer deaths and increased life years gained (LYG) per 100,000 people. Researchers have also suggested that removal of the YSQ criteria may result in a greater than 37 percent increase in lung cancer screening examinations.
Comparing lung cancer screening scenarios that include the criteria of 15 or less years since quitting smoking (< YSQ15) versus scenarios without the YSQ threshold, the researchers found that removing the YSQ threshold led to a greater than 20 percent reduction in lung cancer deaths and a greater than 19 percent increase in life years gained (LYG) per 100,000 people.
Removal of the <YSQ15 criteria also led to a greater than 37 percent increase in lung cancer screening examinations, according to the ACS guideline authors.
In regard to the age limit for lung cancer screening, Wolf and colleagues pointed out that the aforementioned NELSON trial revealed a risk reduction of 23 percent in patients between 70 to 74 years of age, a risk reduction rate that was similar to all other age groups in the study cohort.
Highlighting findings from a 2021 modeling study of annual LDCT screening that informed the United States Preventive Services Task Force (USPSTF) lung screening updates, Wolf and colleagues noted that annual screening benefits extended up to the age of 80 for people who had 15, 20 and 25-pack-year smoking histories.
“ … The totality of the evidence supports annual LCS with LDCT starting at age 50 years and stopping at age 80 years for persons who currently smoke, or formerly smoked, and have accumulated at least 20 pack-years of tobacco smoking, with no consideration of YSQ as an eligibility factor to start or end LCS,” noted Wolf and colleagues.