Updated US guidelines urge more lung cancer screening
Updated guidelines from the American Cancer Society (ACS) recommend that around 5m additional people should be screened for lung cancer, including older adults who smoke or formerly smoked – no matter how long ago they gave up smoking.
Previously, the ACS advised annual lung cancer screening for adults 55 to 74 with at least a 30 pack-year smoking history who either currently smoke or quit smoking less than 15 years ago.
Now, reports CNN, the organisation says regardless of long ago you gave up smoking, this should no longer be a factor in whether you get screened for lung cancer.
In its updated guideline, published in the CA: A Cancer Journal for Clinicians, the society recommends annual lung cancer screening for current or past smokers, aged 50 to 80, with at least a 20 pack-year smoking history.
A pack-year is defined as smoking an average of one pack of cigarettes per day for one year. For instance, someone who smoked two packs a day for 10 years has a 20 pack-year history, as well as someone who smoked one pack a day for 20 years.
Additionally, the updated guideline recommends against “using any duration of years since quitting smoking” as a criterion to start or stop lung cancer screening in former smokers who meet the age and pack-year eligibility criteria.
“I think the years quit was confusing to people,” said Dr William Dahut, chief scientific officer for the American Cancer Society.
“First of all, lung cancer is a disease of the elderly, and so, basically, your risk starts becoming greatest once you’re in your 60s, which was probably during this time period when people were stopping their screening,” he said.
“Over time, we now see that the risk continues for men and women in their 60s and above, and so that is exactly when when you should be screening because that’s when their cancer risk is actually the highest.”
Broadening screening eligibility
The society estimates that its updated recommendation would lead to 21% more lung cancer deaths prevented compared with the current recommendations.
The last time the group updated its lung cancer screening guideline was in 2013. It isn’t the only group in the US that issues cancer screening recommendations.
The US Preventive Services Task Force, a group of independent medical experts whose recommendations help guide doctors’ decisions and influence insurance plans, has its own separate screening advice.
In 2021, the USPSTF issued a final recommendation statement recommending annual screening for lung cancer in adults, ages 50 to 80, with a 20 pack-year smoking history who currently smoke or quit within the past 15 years.
“The USPSTF and other guidelines have always said that the lung cancer screening should apply for people who currently smoke and for people who have quit smoking within the past 15 years,” said Dr Matthew Triplette, a pulmonologist, associate professor and cancer prevention researcher at the Fred Hutchinson Cancer Centre in Seattle, who was not involved in either the ACS or USPSTF recommendations.
“The new guidelines from the American Cancer Society, I think, are reflective of newer modelling evidence. “They are saying risk does not stop when you quit smoking for 15 years and that people who have had that heavy smoking history actually should continue to get screened or should be eligible for screening.”
It’s estimated only about 10% to 15% of all eligible people in the US have been screened for lung cancer.
Surveys of Americans in the 1940s found that about half of all adults said they smoked cigarettes.
Rates began to decline in the 1960s, and last year, about 11% of adults – a historic low – told the US Centres for Disease Control and Prevention (CDC) that they were current cigarette smokers, according to the latest preliminary survey data.
“Recently, at the International Association of Lung Cancer meeting in Singapore, researchers demonstrated that family history is an even stronger predictor of developing lung cancer than smoking. We also know that asbestos exposure is a more potent predictor of lung cancer than smoking.
‘Common sense suggests that these factors should be incorporated into the screening guidelines,” Flores said.
But overall, he added: “The most prevalent misconception about lung cancer is that it is a death sentence. In reality, most lung cancers can be detected early through screening, and most patients with early-detected lung cancers can be saved.”
Screening for lung cancer: 2023 guideline update from the American Cancer Society
Andrew Wolf, Kevin Oeffinger, Tina Ya-Chen Shih, Elizabeth Fontham, et al.
Published in CA: A Cancer Journal on 1 November 2023
Lung cancer is the leading cause of mortality and person-years of life lost from cancer among US men and women. Early detection has been shown to be associated with reduced lung cancer mortality. Our objective was to update the American Cancer Society (ACS) 2013 lung cancer screening (LCS) guideline for adults at high risk for lung cancer. The guideline is intended to provide guidance for screening to health care providers and their patients who are at high risk for lung cancer due to a history of smoking. The ACS Guideline Development Group (GDG) utilized a systematic review of the LCS literature commissioned for the US Preventive Services Task Force 2021 LCS recommendation update; a second systematic review of lung cancer risk associated with years since quitting smoking (YSQ); literature published since 2021; two Cancer Intervention and Surveillance Modelling Network-validated lung cancer models to assess the benefits and harms of screening; an epidemiologic and modelling analysis examining the effect of YSQ and aging on lung cancer risk; and an updated analysis of benefit-to-radiation-risk ratios from LCS and follow-up examinations.
The GDG also examined disease burden data from the National Cancer Institute’s Surveillance, Epidemiology, and End Results program. Formulation of recommendations was based on the quality of the evidence and judgment (incorporating values and preferences) about the balance of benefits and harms. The GDG judged that the overall evidence was moderate and sufficient to support a strong recommendation for screening individuals who meet the eligibility criteria. LCS in men and women aged 50–80 years is associated with a reduction in lung cancer deaths across a range of study designs, and inferential evidence supports LCS for men and women older than 80 years who are in good health.
The ACS recommends annual LCS with low-dose computed tomography for asymptomatic individuals aged 50–80 years who currently smoke or formerly smoked and have a ≥20 pack-year smoking history (strong recommendation, moderate quality of evidence). Before the decision is made to initiate LCS, individuals should engage in a shared decision-making discussion with a qualified health professional. For individuals who formerly smoked, the number of YSQ is not an eligibility criterion to begin or to stop screening. Individuals who currently smoke should receive counselling to quit and be connected to cessation resources. Individuals with comorbid conditions that substantially limit life expectancy should not be screened. These recommendations should be considered by health care providers and adults at high risk for lung cancer in discussions about LCS. If fully implemented, these recommendations have a high likelihood of significantly reducing death and suffering from lung cancer in the United States.