Randomized Controlled Trials of the Efficacy of Lung Cancer Screening by Sputum Cytology Revisited A Combined Mortality Analysis From the Johns Hopkins Lung Project and the Memorial Sloan-Kettering Lung Study

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 under-powered 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 1/2 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 in the X-ray only arm (rate ratio [RR], 0.88; 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 model benefit of sputum cytology screening although we cannot rule out chance as an explanation for these findings. Cancer 2009;115:5007-17. (C) 2009 American Cancer Society.