Despite advances in early detection and treatment, lung cancer remains the leading cause of cancer-related mortality in the United States.1 According to the United States Preventive Services Task Force (USPSTF), an estimated 85% of all lung cancers can be attributed to smoking, a figure that includes both current and former smokers.2 Lung cancer screening (LCS) received a significant boost in 2015 when Medicare and The Affordable Care Act (ACA) announced coverage for eligible individuals, and now screening is widely available throughout the United States. It is estimated that more than 12,000 lives per year could be saved by LCS.3 The American Lung Association reports that the 5-year lung cancer survival rate is now 21.7%, up from 17.2% 10 years ago, in part due to early-stage lung cancer identified through screening.4 Therefore, it is important that healthcare providers recognize who is at high risk for lung cancer, and who could benefit from lung cancer screening. This includes both current and former smokers who meet certain criteria that will be discussed throughout this article.
Lung cancer screening utilizes a CT scan with a lowered dose of radiation to take detailed pictures of the lungs in asymptomatic but high-risk (for lung cancer) patients on an annual basis. The ultimate goal is to detect the presence of lung cancer in its early stages when treatment options are maximized and there is greater chance for a cure.
Research Supports LCS
The National Lung Screening Trial (NLST), completed in 2011, identified a 20% reduction in lung cancer mortality over 3 years in high-risk individuals undergoing annual low-dose CT lung screening. In this landmark study, 51.9% of participants were former smokers.5 Subsequent trials have found an even greater benefit to lung cancer screening, such as the Dutch-Belgium NELSON Trial from 2018, and the Multicentric Italian Lung Detection (MILD) Trial, reported in 2019.6,7 Adding to our understanding of the promise of LCS, the NELSON trail showed a particular benefit to women in screening, and the MILD trial identified that regular screening has increased benefit over time (10 years).6,7
Tobacco Use and Lung Cancer Screening
Tobacco smoking is the greatest risk factor for lung cancer and is found to be implicated in at least 83% of lung cancer-related deaths.8 Former smokers may be more difficult to identify as candidates for lung screening compared with current smokers, even though their risk for lung cancer may be elevated. Therefore, healthcare providers should evaluate the risk of lung cancer in both current and former smokers.
What Does This Mean for Former Smokers?
Thankfully, the rates of cigarette smoking have continued to decline over the past several decades, and there are now more former smokers than current smokers in the United States.9 According to the American Lung Association’s analysis of CDC data, there are 55.2 million former smokers, or about 37% of adults, in the United States.4 This is an important trend, as smoking cessation at any age lowers the risk of lung cancer. It also has both immediate and long-term benefits for those who undergo diagnosis and treatment for lung cancer.10 Former smokers have a 39.1% reduced risk of lung cancer within 5 years of quitting, and this risk continues to lower over time.11 In addition, the younger the age at time of cessation, the greater the benefit.12
That being said, the risk of lung cancer in former smokers remains threefold in comparison with never- smokers, even 25 years after quitting.11 Different studies estimate that almost half of all lung cancer diagnoses occur in former smokers, and that the carcinogenic effect of smoking persists for years after cessation.11,13 In our lung screening program, although this represents a small sample size, 42% of patients diagnosed with lung cancer identified through screening were former smokers. Therefore, it remains critical that we identify former smokers who could benefit from lung cancer screening.
Other Risk Factors for Lung Cancer
Although a history of smoking is the greatest risk factor for lung cancer, there are other important elements to consider when evaluating who might benefit most from lung screening. They includes the following:
Age: The median age at lung cancer diagnosis is 70 years.14 Only 10% of lung cancer cases are seen in people younger than 55 years; 86% of people living with lung cancer in 2015 were 60 years of age or older.4
Race: Certain ethnic backgrounds, such as African American and Native Hawaiian, experience higher rates of lung cancer.15
Education level: Higher rates of smoking are observed in those with less than a high school education. They also might have less access to quality healthcare.16
Environmental and occupational exposures: Recognized carcinogens that attack the lungs include asbestos, radon, coal smoke, and beryllium and silica dust.17
Prior history of cancer: Persons with a history of prior cancer, in particular lung, lymphomas, bladder, or other smoking-related cancers, have a greater risk of new or recurrent lung cancer.18
Family history of lung cancer: Persons with a first-degree relative diagnosed with lung cancer have an increased risk of lung cancer, especially if that relative was a sibling.19
History of a chronic lung disease: Chronic obstructive pulmonary disease (COPD) and pulmonary fibrosis appear to have an independent correlation with lung cancer. A diagnosis of COPD doubles the risk for lung cancer for both current and former smokers.20,21
Underweight: Being underweight is strongly associated with a higher risk of lung cancer. Conversely, those who are considered overweight or obese have a reduced risk of lung cancer.22
Second-hand smoke exposure: Many patients have concerns about second-hand smoke and how that relates to recommendations for lung cancer screening. Research indicates that, in particular, early-in-life exposure poses a greater risk.23 Although this is a known risk factor for lung cancer, it is very difficult to quantify, and it is not currently considered in any lung screening guidelines. The National Comprehensive Cancer Network (NCCN) states that “second-hand smoke does not confer a great enough risk for exposed individuals to be candidates for lung cancer screening.”24
Lung Cancer Screening Guidelines and Coverage
All screening guidelines currently in place consider age and smoking history in their recommendations. However, there is not one universal standard for screening guidelines, which has contributed to the challenge of coordinating and assuring coverage for lung cancer screening.
The first national group to establish lung screening guidelines was the NCCN; the guidelines were completed in 2011 and are updated at least annually.24 These guidelines take into consideration multiple risk factors for lung cancer, not just age and smoking history (Figure).
See the NCCN Guidelines for detailed recommnedations, including footnotes.
The Centers for Medicare & Medicaid Services (CMS) narrowed the scope of eligible Medicare beneficiaries to those between the ages of 55 and 77 years who are current smokers or who quit within 15 years and have at least 30 smoking pack-years, referencing the parameters established in the NLST. The CMS does not consider any additional risk factors in coverage for lung screening.25
The USPSTF largely echoes CMS criteria for lung screening but expands the age recommendation to 80 years. Like the CMS, screening is covered for those adults who have a 30 pack-year smoking history and currently smoke or who quit within the past 15 years. These guidelines also do not consider additional risk factors.2
Both the CMS and the USPSTF state that 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
Of note, the NCCN Lung Cancer Screening Guidelines state that “limiting use to the NLST criteria is arbitrary and naïve, because the NLST only used age and smoking history for inclusion criteria and did not consider other well-known risk factors for lung cancer.”24
Private insurance generally follows USPSTF guidelines and has been mandated by the ACA to offer lung cancer screening benefits for eligible patients.26 See Table for Eligibility Criteria for Lung Cancer Screening.
What About Medicaid?
Medicaid beneficiaries are at higher risk for lung cancer than the rest of the population, demonstrating higher overall smoking rates and lower overall 5-year lung cancer survival rates. At the same time, states are not required to provide lung screening coverage through all Medicaid programs. Many state programs do offer screening benefits, but criteria for coverage and copays vary, so it is best to check with your state’s Medicaid plan.27
What Does This Mean for Those Who Do Not Meet Criteria?
There are individuals who fall under the high-risk category per NCCN guidelines who are not included in insurance-covered criteria by CMS or by private insurances following USPSTF guidelines. In fact, according to the Framingham Heart Study, only 58.7% of patients identified with lung cancer met CMS criteria for screening.11 Often this is because they have not “smoked enough,” quit smoking more than 15 years ago, or “aged out” of CMS criteria coverage.
In such cases, of which there are many, it can be helpful to utilize a screening tool to determine an individual’s risk of lung cancer. Whereas there are many tools available, one very user-friendly website is shouldiscreen.com, developed by the University of Michigan.28,29 This online screening questionnaire incorporates many risk factors for lung cancer to generate a percentage risk of lung cancer in the next 6 years while utilizing USPSTF guidelines and NLST data. This can be helpful for identifying those at high risk for lung cancer, including those who fall out of eligibility criteria from the standpoint of CMS or private insurance.
The following scenarios use the shouldiscreen.com tool for former smokers. They reveal great variability in the benefit of screening in former smokers, regardless of their eligibility for insurance coverage.
George is 78-year-old Caucasian gentleman in relatively good health with a history of bladder cancer, high blood pressure, and COPD. He successfully quit smoking 16 years ago, but he did smoke 2 packs per day for 40 years (80 pack-years). He is 72″ tall, weighs a slim 150 lbs, and is a retired carpenter with a high school diploma. He is very concerned about lung cancer for himself because his brother recently died of lung cancer. He has Medicare for his primary insurance. Should George get a lung screening?
According to the shouldiscreen.com questionnaire, George’s 6-year risk of lung cancer is 26.2%, clearly putting him in the high-risk category. Unfortunately, based on CMS criteria, George is not eligible because he is older than 77 years and quit smoking more than 15 years ago. However, his significant pack-year history, bladder cancer history, family lung cancer history, and underweight status increase his lung cancer risk. So, George could be offered a self-pay option for lung screening with a provider’s order, which is available at many lung screening facilities.
Jana is a 55-year-old Caucasian woman who has no significant medical history. She was a heavy smoker for 25 years but quit smoking 14 years ago (1.5 packs per day × 25 years equals 37.5 pack-years). Jana is a psychology professor at a local university, is 5′4″ and weighs 180 lbs. She has no personal history of cancer, no family history of lung cancer, and no history of any chronic lung diseases. Should Jana get a lung screening?
According to USPSTF criteria, which her private insurance would follow, Jana is eligible for a lung screening. However, based on her history, Jana only has a 0.4% risk of lung cancer in the next 6 years according to the should iscreen.com tool. Jana can be offered lung screening, but a further discussion may reveal it is not considered to be of great benefit because her overall risk of lung cancer is low.
Martin is a 68-year-old African American with a history of hypertension, hypersensitivity lung disease, coronary artery disease, and early-stage COPD; he has no personal history of cancer and no family history of lung cancer. He recently retired from his post as security officer at a local hospital (he says he completed some college, but left to work in the security field). Martin successfully quit smoking 8 years ago after 42 years of smoking cigarettes (averaging about 1 pack per day). Martin is 5′11″ and weighs 180 pounds.
Martin’s risk for lung cancer in the next 6 years is estimated at 5.2%. He qualifies for insurance-covered screening and fits into the high-risk category in which lung screening is considered beneficial.
A Word About Shared Decision-Making
Medicare requires a formal shared decision-making visit (with the billable code of G0296) at initiation of lung screening. This counseling time can be used to review individual risk for former smokers, such as those in the case studies, as well as to reveal personal preferences and values.25 Counseling for non-Medicare patients is also highly valuable considering the complexities of determining who stands to benefit the most from annual lung screening.
Why Can’t We Just Screen Everybody?
Lung screening performs at its best in asymptomatic participants with a high risk of lung cancer who are generally healthy and willing to undergo treatment if cancer is detected.
Like all screening methods, there are harms associated with lung cancer screening. Those at lower risk for lung cancer stand to have less benefit but are subjected to the same potential harms. Largely this includes the scare of false alarms for lung nodules that require follow-up imaging but never result in a lung cancer diagnosis. In a small group of people, however, this may result in an invasive procedure, such as a biopsy, which has known risks of infection, hospitalization, and, although extremely rare, death. There is also the cumulative risk of radiation exposure from annual CT scans. However, this is largely mitigated by reducing the radiation dose to about one-fifth of a standard CT scan. Furthermore, there are costs associated with screening and any additional testing required that cannot be ignored.2,5,25
Lung cancer screening for those at high-risk has the potential to save thousands of lives annually by catching lung cancer in its early stages. Current and former smokers who have quit within 15 years, have at least a 30 pack-year smoking history, and are between the ages of 55 and 77 years are generally eligible for lung screening coverage. However, those who fall out of the eligibility criteria may still be at high risk for lung cancer and would benefit from a case-by-case analysis of their own personal risk. Healthcare providers have a critical role to play in recognizing both current and former smokers at high risk for lung cancer. Further research is needed to support refinement in identifying those most at risk for lung cancer, and thus, those who stand to benefit the most from screening.
- Siegel RL, Miller KD, Jemal A. Cancer Statistics, 2019. CA Cancer J Clin. 2019;69:7-34.
- Moyer VA. Screening for Lung Cancer: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2014;160:330-338.
- Ma J, Ward EM, Smith R, Jemal A. Annual number of lung cancer deaths potentially avertable by screening in the United States. Cancer. 2013;119:1381-1385.
- American Lung Association. State of Lung Cancer: Key Findings. www.lung.org/research/state-of-lung-cancer/key-findings. Updated March 12, 2020. Accessed March 24, 2020.
- Aberle DR, Adams AM, Berg CD, et al. Reduced lung-cancer mortality with low-dose computed tomographic screening. N Engl J Med. 2011;365:395-409.
- de Koning HJ, Van der Aalst CM, de Jon PA, et al. Reduced lung-cancer mortality with volume CT screening in a randomized trial. N Engl J Med. 2020;382:503-513.
- Pastorino U, Silva M, Sestini S, et al. Prolonged lung cancer screening reduced 10-year mortality in the MILD trial: new confirmation of lung cancer screening efficacy. Ann Oncol. 2019;30:1162-1169.
- US Department of Health & Human Services. The Health Consequences of Smoking: 50 Years of Progress. A Report of the Surgeon General. Atlanta, GA: US Department of Health & Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2014. Printed with corrections, January 2014.
- Chest Foundation. Facts about tobacco. https://foundation.chestnet.org/wp-content/uploads/2017/07/Tobacco-Mythbusters071917.pdf. Accessed March 25, 2020.
- Cataldo JK, Dubey S, Prochaska JJ. Smoking cessation: an integral part of lung cancer treatment. Oncology. 2010;78:289-301.
- Tindle HA, Stevenson Duncan M, Greevy RA, et al. Lifetime smoking history and risk of lung cancer: results from the Framingham Heart Study. J Natl Cancer Inst. 2018;110:1201-1207.
- Halpern MT, Gillespie BW, Warner KE. Patterns of absolute risk of lung cancer mortality in former smokers. J Natl Cancer Inst. 1993;85:457-464.
- Mong C, Garon EB, Fuller C, et al. High prevalence of lung cancer in a surgical cohort of lung cancer patients a decade after smoking cessation. J Cardiothorac Surg. 2011,6:19.
- Howlader N, Noone AM, Krapcho M, et al. SEER Cancer Statistics Review, 1975-2016, based on November 2018 SEER data submission, posted to the SEER web site, April 2019. Bethesda, MD: National Cancer Institute; 2019. https://seer.cancer.gov/csr/19752016.
- Haiman CA, Stram DO, Wilkens LR, et al. Ethnic and racial differences in the smoking-related risk of lung cancer. N Engl J Med. 2006; 354:333-342.
- Mouw T, Koster A, Wright ME, et al. Education and risk of cancer in a large cohort of men and women in the United States. PLoS One. 2008; 3:e3639.
- Field RW, Withers BL. Occupational and environmental causes of lung cancer. Clin Chest Med. 2012;33:681-703.
- Wu GX, Nelson RA, Kim JY, Raz DJ. Non-small cell lung cancer as a second primary among patients with previous malignancy: who is at risk? Clin Lung Cancer. 2017;18:543-550.
- Cote ML, Liu M, Bonassi S, et al. Increased risk of lung cancer in individuals with a family history of the disease: a pooled analysis from the International Lung Cancer Consortium. Eur J Cancer. 2012;48:1957-1968.
- Durham AL, Adcock IM. The relationship between COPD and lung cancer. Lung Cancer. 2015;90:121-127.
- Ballester B, Milara J, Cortijo J. Idiopathic pulmonary fibrosis and lung cancer: mechanisms and molecular targets. Int J Mol Sci. 2019;20:593.
- Duan P, Hu C, Quan C, et al. Body mass index and risk of lung cancer: systematic review and dose-response meta-analysis. Sci Rep. 2015;5:16938.
- Asomaning K, Miller DP, Liu G, et al. Second hand smoke, age of exposure and lung cancer risk. Lung Cancer. 2008;61:13-20.
- National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) Lung Cancer Screening. V.1.2020. www.nccn.org/professionals/physician_gls/pdf/lung_screening.pdf.
- Centers for Medicare & Medicaid Services. Decision Memo for Screening for Lung Cancer with Low Dose Computed Tomography (LDCT) (CAG-00439N). www.cms.gov/medicare-coverage-database/de tails/nca-decision-memo.aspx?NCAId=274. Published February 5, 2015. Accessed March 30, 2020.
- Agency for Healthcare Research and Quality. Lung Cancer Screening: A Summary Guide for Primary Care Clinicians. https://effectivehealth care.ahrq.gov/decision-aids/lung-cancer-screening/clinician-summary.html. Published March 2016. Accessed March 2020.
- American Lung Association. Access to Lung Cancer Screening in Medicaid. www.lung.org/getmedia/d028d8c6-edc5-4434-92d2-e98ab1ee2783/access-to-lung-cancer-1.pdf. Updated 2019. Accessed March 25, 2020.
- Lau YK, Caverly TJ, Cherng ST, et al. Development and validation of a personalized, web-based decision aid for lung cancer screening using mixed methods: a study protocol. JMIR Res Protoc. 2014;3:e78.
- University of Michigan. Lung Cancer Screening. Should I Get Screened? https://shouldiscreen.com/English/home. Updated March 31, 2020. Accessed March 31, 2020.