Early detection in lung cancer. Case finding and screening.
There is general agreement that the most effective approach to lung cancer is primary prevention--stop smoking. Richards has proposed the MVROCST--the Monosyllabic Verbal Response Office Cancer Screening Test: "Do you smoke?" If "yes," intervene. If "no," move on. Ample evidence exists that a clear message from a physician to a patient about the importance of stopping smoking makes a difference. In contrast to the maze of arguments and data on early detection, this is something that each physician clearly can and should do. A reduced risk for lung cancer may begin as early as 5 years after cessation of cigarette use. Huuskonen has proposed conceptualizing screening as a coordinated intervention with the goal of identifying populations at risk and working to modify that risk. Primary prevention should be central to any efforts to reduce mortality from lung cancer, and attention to this area needs to increase despite the difficulties and frustration. Despite declining percentages of smokers in the population as a whole, it is estimated that more than 3000 teenagers become regular smokers each day in the United States. In this environment, the question of whether to recommend a CXR or sputum for early detection is not going to disappear in the near future. The NCI has recognized the persistent and important nature of this debate and is currently funding the Prostate, Lung, Colon and Ovary Cancer Screening Trial. This is a large and powerful randomized study of men and women aged 60 to 74. The lung cancer arm is designed to look at the usefulness of a yearly CXR intervention in reducing cancer-specific mortality. The overall power of the study (based on national mortality data) is 0.99 for a 15% reduction in lung cancer mortality and 0.89 for a 10% reduction, with differentially better sensitivity in men than women. The study is currently in progress at multiple sites and will be completed over the next 12 to 14 years. In the meantime, what is the right approach? It is useful in considering this question to return to the concepts of early detection, screening, and case finding. 1. Early detection in lung cancer remains a concept of uncertain applicability because of the unknowns and variability in the natural history of the disease. The available, accessible, and acceptable detection tools appear to be inadequate by current evidence. This is not a static field, however, and new work in the area of biomarkers carries promise for significantly more sensitive and specific techniques. Tockman and colleagues conclude that early detection is conceptually sound, although not currently practical, and further research may expand the role of intervention. In the end, a judgement on early detection in lung cancer must be linked to the proposed setting--screening or case finding. 2. Screening, defined as the application of a test to the general population to define disease risk further with the implied benefit of improved treatment and outcome, cannot be recommended for lung cancer. This is the perspective of the major organizations cited previously, and it is based on admittedly imperfect but nonetheless convincing data. 3. Case finding, the situation of the patient who seeks care and is available for informed discussion and negotiation on possible testing, is a potentially different situation.(ABSTRACT TRUNCATED)
Wolpaw
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Division of General Internal Medicine and Health Care Research, Case Western Reserve University, Cleveland, Ohio, USA.
D003663:Decision Trees; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control*; D008403:Mass Screening / Q000379:methods*; D015995:Prevalence; D011322:Primary Prevention; D012307:Risk Factors; D012680:Sensitivity and Specificity