Lung Cancer Imaging in Asymptomatic Patients: To Screen or Not to Screen?

“We have high quality evidence that screening reduces overall mortality (5 deaths per 1000 screened participants, of which 3 deaths are due to lung cancer),” said Bruno Heleno, MD, PhD, assistant professor at NOVA Medical School at the University of Lisbon in Portugal in an email to Pulmonology Advisor. “The evidence about overdiagnosis is of moderate quality due to inconsistency. With LCS, 5 participants (NLST estimate) may be diagnosed with a cancer that does not progress to symptoms or death. This number may be as high as 16 participants (Danish Lung Cancer Screening Trial estimate) or as low as 0 participants (Italian Lung Cancer Screening Trial estimate).”

The highest risk category for LCS in the American Association for Thoracic Surgery (AATS) guidelines are those individuals ages 55 to77 years with a 30 pack-year history.7 However, it lowered the recommended screening age to 50 years for patients with a 20 pack-year history of smoking if their 5-year risk for lung cancer gives them a >5% risk.7 AATS includes other factors for screening: patients with chronic obstructive pulmonary disease with forced expiratory volume in 1 second of 70% or less than predicted, environmental or occupational exposures, previous cancer or chest radiation, and family history.7

Like the AATS, the National Comprehensive Cancer Network (NCCN) has more than one risk category.8 The NCCN, however, recommends screening only for patients in the high-risk group. ACCP, NCCN, USPSTF, and Centers for Medicare & Medicaid Services (CMS) advocate shared decision making between clinicians and their patients to discuss the risks and benefits of LCS.9,10

Shared Decision Making Is Nonexistent

CMS requires clinicians to implement shared decision making when discussing LCS options.11 Brenner and colleagues found that despite the CMS mandate, clinicians are not complying by discussing the benefits and harms of LCS by analyzing anonymized conversations between pulmonologists or primary care physicians and their patients (N=14).12 Half of the providers were in primary care and 8 patients were current smokers.12

During the office visits they studied, the mean encounter lasted 13:07 minutes, of which 0:59 seconds were devoted to LCS, or 8% of the visit.12 Clinicians also did not use decision aids or other patient education leaflets.12 Primary care physicians and pulmonologists had comparable mean scores (from 0 to 100), 7 vs 5, respectively.12  

“Clinicians should tell patients there is a decision to be made, that their input is needed, and that it will require time to discuss,” said coauthor Daniel S. Reuland, MD, MPH, professor of medicine, cancer prevention and control at the University of North Carolina-Chapel Hill in an email interview with Pulmonology Advisor. “Clinicians and patients should then plan for the discussion, now or at a future visit. Most importantly, they should use a decision aid and make an authentic effort to convey the idea that tradeoffs are involved.”

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Particularly striking was the 98% rate of false-positive LDCT screening, and yet none of the clinicians in the study disclosed this harm to patients during an office visit.11 Not only would additional testing provoke anxiety, it would also subject patients to potential biopsies or lobectomies.11

What might account for clinicians not including shared decision making in their visits? A national survey of 293 primary care providers revealed that 75% thought the benefits of LCS outweighed the risks and that other health concerns squeezed the time allotted for shared decision making (42%).13

“Patient visits are already busy, but it is essential to be able to allow enough time for discussion of harms and benefits of LCS,” said cardiologist Rita F. Redberg, MD, MSc, editor of JAMA Internal Medicine and professor of medicine at the University of California San Francisco in an email to Pulmonology Advisor. “There are a number of available decision aids that can help, but not replace the patient-physician discussion.”

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Summary & Clinical Applicability

Lung cancer screening for individuals with a low risk for lung cancer remains controversial, even after the publication of the National Lung Screening Trial. Despite the 20% reduction in lung cancer deaths because of the screening, skeptics claim the risk-to-benefit ratio is not valid because subsequent studies have shown high rates of overdiagnosis. Proponents advocate less rigid guidelines to detect lung cancer early in asymptomatic patients with high-risk factors beyond age and smoking history.

Limitations & Disclosures



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  9. Centers for Medicare & Medicaid Services. Decision memo for screening for lung cancer with low dose computed tomography (LDCT) (CAG-00439N). Accessed August 20, 2018.
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  11. Redberg RF. Failing grade for shared decision making for lung cancer screening [published online August 13, 2018]. JAMA Intern Med. doi:10.1001/jamainternmed.2018.3527
  12. Brenner AT, Malo TL, Margolis M, et al. Evaluating shared decision making for lung cancer screening [published online August 13, 2018]. JAMA Intern Med. doi:10.1001/jamainternmed.2018.3054
  13. Eberth JM, McDonnell KK, Sercy E, et al. A national survey of primary care physicians: perceptions and practices of low-dose CT lung cancer screening. Prev Med Rep. 2018;11:93-99.