Randomized controlled trials of the efficacy of lung cancer screening by sputum cytology revisited |
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| Authors: | V. Paul Doria‐Rose DVM PhD Pamela M. Marcus PhD Eva Szabo MD Melvyn S. Tockman MD PhD Myron R. Melamed MD Philip C. Prorok PhD |
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| Affiliation: | 1. Biometry Research Group, Division of Cancer Prevention, National Cancer Institute, National Institutes of Health, Bethesda, Maryland;2. Cancer Prevention Fellowship Program, Center for Cancer Training, National Cancer Institute, National Institutes of Health, Bethesda, Maryland;3. Fax: (301) 402‐0816;4. Lung and Upper Aerodigestive Cancer Research Group, Division of Cancer Prevention, National Cancer Institute, National Institutes of Health, Bethesda, Maryland;5. Risk Assessment, Detection, and Intervention Program, Department of Cancer Prevention and Control, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida;6. Department of Pathology, New York Medical College, Valhalla, New York |
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| Abstract: | BACKGROUND: Two randomized controlled trials of lung cancer screening initiated in the 1970s, the Johns Hopkins Lung Project and the Memorial Sloan‐Kettering Lung Study, compared 1 arm that received annual chest X‐ray and 4‐monthly sputum cytology (dual‐screen) to a second arm that received annual chest X‐ray only. Previous publications from these trials reported similar lung cancer mortality between the 2 groups. However, these findings were based on incomplete follow‐up, and each trial on its own was underpowered to detect a modest mortality benefit. METHODS: The authors estimated the efficacy of lung cancer screening with sputum cytology in an intention‐to‐screen analysis of lung cancer mortality, using combined data from these trials (n = 20,426). RESULTS: Over ½ of squamous cell lung cancers diagnosed in the dual‐screen group were identified by cytology; these cancers tended to be more localized than squamous cancers diagnosed in the X‐ray only arm. After 9 years of follow‐up, lung cancer mortality was slightly lower in the dual‐screen than in the X‐ray only arm (rate ratio [RR], 0.88; 95% confidence interval [CI], 0.74‐1.05). Reductions were seen for squamous cell cancer deaths (RR, 0.79; 95% CI, 0.54‐1.14) and in the heaviest smokers (RR, 0.81; 95% CI, 0.67‐1.00). There were also fewer deaths from large cell carcinoma in the dual‐screen group, although the reason for this is unclear. CONCLUSIONS: These data are suggestive of a modest benefit of sputum cytology screening, although we cannot rule out chance as an explanation for these findings. Cancer 2009. © 2009 American Cancer Society. |
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| Keywords: | lung cancer screening sputum cytology chest X‐ray |
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