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 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 (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 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. (c) 2009 American Cancer Society.
Doria-Rose
V Paul
VP
Biometry Research Group, Division of Cancer Prevention, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA. doriarop@mail.nih.gov
Marcus
Pamela M
PM
Szabo
Eva
E
Tockman
Melvyn S
MS
Melamed
Myron R
MR
Prorok
Philip C
PC
D000368:Aged; D003581:Cytodiagnosis / Q000379:methods*; D055088:Early Detection of Cancer; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000401:mortality / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011859:Radiography; D013183:Sputum / Q000166:cytology*