Abstract:
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Purpose: To assess whether chest radiographic screening for lung cancer
leads to a reduction in lung cancer specific mortality.
Methods and Materials: Lung cancer specific mortality can be derived in a
screened population based on the knowledge of how frequently the screening
finds cancer by stage and, once this is known, how frequently cure is achieved
with and without treatment. These facts allow for estimation of the overall
cure rate by subtype which can used to derive the lung cancer specific
mortality reduction. Information on the stage distribution of cancers detected
in the screening arm of the Mayo Lung Project (MLP), including those detected
by chest radiography, was obtained from data supplied by the National Cancer
Institute. In a previous analysis, we estimated the proportion of lung cancers
that would not progress in the absence of treatment (proportion of
overdiagnosis). In this study, we estimated the lung cancer specific mortality
reduction based on knowledge of the cure rates, the proportion of
overdiagnosis, and the proportion of cancers in different stages detected under
screening in the MLP.
Results: In the six years of high-frequency screening following the prevalence
screen in the MLP, the proportion of Stage I lung cancers detected was 53%, the
proportion of Stage II cancers was 3%, and the proportion of Stage III cancers
was 43%. The proportion of overdiagnosis was estimated to be 10%. The cure
rates derived from long term survival of Stage I lung cancers with and without
treatment was 67%, and for advanced stages was negligible. Using this
information, the estimated reduction in lung cancer specific mortality was
estimated to be 35%.
Conclusion: Use of a methodology that directly derives the lung cancer specific
mortality reduction shows that in the MLP, chest radiographic screening was
beneficial. (This work was supported in part by a grant from General Electric.)
Yankelevitz MD, D,
The Mayo Lung Project: Another Look, a Different View. Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL.
http://archive.rsna.org/2003/3108686.html
