From the Pulmonary, Allergy and Critical Care Division (Drs Courtright and Manaker), Hospital of the University of Pennsylvania (Drs Courtright and Manaker), and Department of Medicine (Dr Manaker), University of Pennsylvania.
CORRESPONDENCE TO: Katherine Courtright, MD, Pulmonary, Allergy and Critical Care Division, Hospital of the University of Pennsylvania, Gates Bldg, 806 W, 3400 Spruce St, Philadelphia, PA 19104; e-mail: firstname.lastname@example.org
FINANCIAL/NONFINANCIAL DISCLOSURES: The authors have reported to CHEST the following conflicts of interest: Dr Manaker has received fees as a grand rounds speaker, lecturer, consultant, and expert witness on documentation, coding, billing, and reimbursement from hospitals, physicians, departments, practice groups, professional societies, insurers, and various attorneys. In March 2011, he received $5,400 from Aetna Inc for consultation on diagnosis coding. He serves on the Hospital Outpatient Panel, a federal advisory commission to the Centers for Medicare & Medicaid Services; serves on the Contractor Advisory Committee for Novitas Solutions, Inc, a Medicare contractor; and chairs the Practice Expense Subcommittee of the American Medical Association, Specialty Society Relative Value Unit Update Committee. Dr Manaker also serves on the board of directors of ACCP Enterprises, Inc, a wholly owned, for-profit subsidiary of the American College of Chest Physicians. Dr Courtright has reported that no potential conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.
Reproduction of this article is prohibited without written permission from the American College of Chest Physicians. See online for more details.
We appreciate Dr Yankelevitz’s1 discussion favoring coverage for lung cancer screening with low-dose CT (LDCT) scanning and agree with many of his thoughtful points. The divergent viewpoints expressed in this debate stem from the philosophical question of whether the glass is half empty or half full. The former approach best aligns with the ethical principles underlying preventive medicine, specifically that all potential harms are held to the highest level of scrutiny. Thus, we are obliged to confess, not underestimate or necessarily accept, the gaps in evidence for LDCT scan screening.
The National Lung Screening Trial (NLST) offers the primary evidence for LDCT scan effectiveness.2 With the Medicare-aged population overrepresented in lung cancer diagnoses yet severely underrepresented in the NSLT, it is crucial to further explore the risks and benefits specific to screening patients in this age-group. Secondary analyses of the NLST population found that although the Medicare-eligible cohort did experience a risk reduction in mortality with LDCT scan screening,3 this mortality benefit may be mitigated by their significantly higher false-positive rate and tendency to undergo invasive procedures compared with participants aged < 65 years.4 Additionally, the healthy volunteer effect present among all ages in the NLST tends to overestimate mortality benefits and further calls into question the strikingly low rates of surgical mortality in both age-groups.4 Finally, the efficiency of screening older patients with a higher positive predictive value because of their increased prevalence of lung cancer diagnoses may be attenuated by the 2.4-fold increased rate of lung cancer death compared with the younger cohort.4 In brief, the cumulative evidence is insufficient to determine the balance between mortality benefits and disproportionate harms of LDCT scan screening in an older population and, indeed, raises the possibility that it is unfavorable.
Dr Yankelevitz1 asserts that the magnitude of survival benefit after three rounds of LDCT scan screening in the NLST may be higher with additional rounds but neglects to consider the flip side: the additional harms. For example, a study examined the hypothetical (yet plausible) cumulative radiation dose of positively screened NLST participants who then receive serial imaging per the Fleischner Society guidelines for 2 to 3 decades. Such patients would accumulate radiation doses, and the accompanying increased risk of radiation-related lung cancer, far exceeding those of nuclear industry workers and atomic bomb survivors.5 Regardless of the reasons, 3 years was chosen in the NLST, and 3 years is the only duration of screening with empirical data suggesting an ostensibly negligible radiation risk, although cumulative radiation doses were not directly measured.2
Furthermore, reporting a cure rate does not inform whether the screening test saves lives because this statistic neglects both overdiagnosis and lead time bias. The importance of these two well-described harmful effects of any cancer screening test are perhaps best exemplified by the deescalation of mammography screening recommendations over time.6 Increased detection and resection of often clinically insignificant adenocarcinoma in situ nodules, for example, will inflate observed lung cancer survival and cure rates, considered by some to be an example of misrepresenting data.7
We are not universally opposed to LDCT scan screening for lung cancer but believe that it is prudent to proceed with caution. Specifically, rather than a broad, indiscriminate coverage decision, we would favor limiting screening programs to highly specialized centers, as in the NLST, and limiting screening recommendations and coverage to patients in whom the mortality benefits clearly outweigh the potential harms. A widespread screening campaign risks inappropriately generalizing results from a single, highly controlled trial and allowing for nodule resection to become the pulmonary equivalent of the oculostenotic reflex.8
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