. "7. Adopting New Technology in the Face of Uncertain Science: The Case of Screening for Lung Cancer." Fulfilling the Potential for Cancer Prevention and Early Detection. Washington, DC: The National Academies Press, 2003.
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Fulfilling the Potential of Cancer Prevention and Early Detection
Eddy wrote, “The Society has changed its policy and does not recommend any tests for the early detection of cancer of the lung, but urges a focus on primary prevention: helping smokers to stop (or switch to low tar and nicotine cigarettes), and keeping nonsmokers from starting. People with signs and symptoms of lung cancer should consult their physicians” (p. 205). The rationale for the policy change was that screening techniques must reduce morbidity and mortality from the disease, which these trials clearly did not establish. Furthermore, harm from screening due to false-positive workups and iatrogenic complications with corresponding costs would make such screening unattractive. The NCI trials were done at respected academic medical centers with well-trained health care professionals. If widespread mass screening were incorporated, the rates of workups because of false-positive results and subsequent harm would rise, given the inexperience and wide variability in the quality of care. A lack of experienced cytologists to read the sputum smears was cited as an example of the limitations of the infrastructure available for the implementation of widespread mass screening.
The American Cancer Society’s position paper did leave the door open for change: “Although at present there is insufficient evidence that screening is effective in reducing lung cancer mortality, there is no proof that it is not effective. As stated before, every case is different, and it may be that even knowing the lack of evidence of benefit and the potential risks, some individuals may choose to have early detection examinations. The Society’s recommendations are not meant to discourage this” (Eddy, 1980a, p. 206).
A U.S. Preventive Services Task Force (1990) position paper stated, “screening asymptomatic persons for lung cancer with routine chest radiographs or sputum cytology is not recommended” (p. 1763). They noted “accuracy of the chest radiograph is limited by the capabilities of the technology and by variation in interpretation among radiologists” (p. 1763). “Furthermore, the yield of screening chest radiography to detect cancer is low, largely because of the low prevalence of lung cancer in the general population and even among asymptomatic smokers” (p. 1763) and the low yield due to the uncommon nature of the disease. The NCI prevalence data indicate that only 0.39 percent of the screened population had lung cancer. Sputum cytology was a less effective technique since chest radiography detected the majority of cancers. The paper concluded that $1.5 billion would be spent if mass screening for high-risk groups was advocated and that there would be significant harm from follow-up testing. It concluded, “Primary prevention may be more effective ... cigarette smoking is responsible for more than 90 percent of lung cancers and should therefore be the principal focus of clinical efforts to help prevent this disease” (U.S. Preventive Task Force, 1990, p. 1765).
The NCI, the Food and Drug Administration, the American College of