The American Cancer Society has updated its screening guidelines for lung cancer, the leading cause of cancer-specific deaths in the United States and the largest driver of potential years of life lost from cancer.
The 2023 screening guidance, aimed principally at reducing lung cancer mortality in asymptomatic but high-risk, tobacco-exposed individuals, expands the age eligibility and lowers both the former smoking history and the years since quitting threshold for screening with low-dose CT (LDCT).
It is based on the most recent evidence on the efficacy and effectiveness of screening and lung cancer risk in persons who formerly smoked, wrote the ACS's Guideline Development Group led by Robert A. Smith, PhD, senior vice president of early cancer detection science. The new guidelines, which replace the 2013 statement, appear in CA: A Cancer Journal for Physicians.
The primary evidence source for the update was a systematic review of LDCT lung cancer screening conducted for the U.S. Preventive Services Task Force and published in 2021.
The new guideline continues a trend of expanding eligibility for lung cancer screening, which has had low uptake, to prevent more deaths. "Recent studies have shown that extending the age for persons who smoked and formerly smoked, eliminating the 'years since quitting' requirement, and lowering the pack-per-year recommendation could make a real difference in saving lives," Dr. Smith said. "The relative risk of developing lung cancer in people who have smoked most of their life compared to people who never smoked is very high — about 70 times the risk." Although lung cancer is the third most common malignancy in the United States, it accounts for more deaths than colorectal, breast, prostate, and cervical cancers combined.
The recommendation for annual LDCT for at-risk persons remains unchanged from 2013.
Among the 2023 eligibility changes:
Age: Expanded to 50-80 years from 55-74 years.
Smoking status: Changed to current or previous smoker from current smoker or smoker who quit within past 15 years (number of years since quitting no longer a criterion to start or stop screening). Dr. Smith noted that both the 2013 guidelines and other groups' updated recommendations retained the eligibility cutoff of 15 years since smoking cessation. "But had their risk declined to a level that just did not justify continuing screening?" he asked. "There wasn't an answer to that question, so we needed to look carefully at the absolute risk of lung cancer in persons who formerly smoked compared with people who currently smoked and people who never smoked."
Smoking history: Reduced to 20 or more pack-years (average of 20 cigarettes a day) versus 30 or more pack-years.
Exclusions: Expanded to health conditions that may increase harm or hinder further evaluation, surgery, or treatment; comorbidities limiting life expectancy to fewer than 5 years; unwillingness to accept treatment for screen‐detected cancer, which was changed from 2013's life‐limiting comorbid conditions, metallic implants or devices in the chest or back, home oxygen supplementation.
In addition, decision-making should be a shared process with a health professional providing the patient with information on the benefits, limitations, and harms of LDCT screening, as well as prescreening advice on smoking cessation and the offer of assistive counseling and pharmocotherapy.
"Overall, lung cancer screening remains one of the least used early cancer detection modalities in clinical practice. The new guidance opens up lung cancer screening to all former smokers regardless of time of cessation," said internist William E. Golden, MD, MACP, a professor of medicine and public health at the University of Arkansas for Medical Sciences, Little Rock. "This may promote greater uptake in concert with greater availability of low-radiation CT scanning."
While agreeing the expanded criteria will enfranchise nearly 5 million current and former U.S. smokers for screening and may reduce deaths, internist Aarati D. Didwania, MD, MMSCI, MACP, a professor of medicine and medical education at Northwestern University, Chicago, warned that increasing actual uptake may be an uphill battle. "The practical part of the equation is seeing that the scans get done. There is often a lag between a recommendation of a yearly test and getting insurance coverage for it, and many disadvantaged people face barriers." Then there's the knowledge gap. "Patients and doctors have to know what the new guidelines are and who has access," she said.
Reaching the target population in rural areas is particularly challenging with the greater distances to imaging centers. Another barrier is that most electronic health records do not identify eligible patients based on smoking and pack‐year history.
In Dr. Didwania's view, professional medical societies have an important role to play in educating their members, and through them, patients. "Disseminating information about the new recommendations is the first step and would be incredibly helpful."
A brief history of lung cancer screening
1950s: By mid-20th century, the causal association between tobacco exposure and lung cancer became clear and by the late 1950s attempts were made to develop a lung cancer screening strategy for high‐risk individuals, commonly with the combination of sputum cytology and chest x-ray.
1970s: The ACS recommended annual testing for current or former smokers with chest x-ray (and sometimes sputum cytology).
1980: The ACS withdrew the above recommendation for regular radiographic screening after randomized controlled trials failed to yield convincing evidence that such screening saved lives.
2013: After the National Lung Screening Trial found three annual LDCT screenings were associated with a 20% relative mortality reduction, compared with annual chest x-ray, the ACS issued a recommendation for annual screening with LDCT: in persons 55-74 years with a pack‐year history of 30 or more who currently smoke or formerly smoked but had not exceeded 15 years since quitting and had no life-limiting morbidity.
Future mortality
Although tobacco controls are expected to reduce age‐adjusted lung cancer mortality in the United States by 79% from 2015 to 2065, 4.4 million lung cancer deaths are projected to occur in this period, the authors stated. "A large fraction of these deaths can be prevented if we embrace the urgent challenge to improve our ability to identify the population at risk and apply our knowledge to achieve high rates of participation in regular [lung cancer screening]."
The study was funded by the American Cancer Society Guideline Development Group and the National Comprehensive Cancer Network. The authors disclosed no relevant competing interests. Dr. Golden and Dr. Didwania had no relevant conflicts of interest to declare with regard to their comments.
This article originally appeared on MDedge.com, part of the Medscape Professional Network.
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Cite this: ACS Expands Lung Cancer Screening Eligibility - Medscape - Nov 03, 2023.
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