| Summary: | Lung cancer continues to be the leading cause of cancer death in Canada. Thirty percent of
cancer deaths in men and one-quarter in women are due to lung cancer alone. Prognosis is better
for patients diagnosed with early stage lung cancer (>80% 5 year relative survival) than those
with late stage cancer (<10% 5 year relative survival). Screening for early stage lung cancer,
before the onset on clinical symptoms, leads to a reduction in risk of invasive cancer. In order for
a cancer screening programme to be recommended as a cancer control strategy, certain
fundamental criteria must be fulfilled, one of which is the cost-effectiveness of the proposed
screening test.
To facilitate funding allocations of scarce resources across health care programs, economic
evaluation models are used to compare the cost-effectiveness of different health interventions. In
this model, the cost-utility of using automated sputum cytometry (ASC) versus spiral CT alone
as a first step in screening for early stage lung cancer is determined.
ASC consists of a high-resolution quantitative microscopy system that analyzes the
concentration and distribution of DNA and chromatin structures within the cell nucleus of
sputum cells. This will determine the likelihood of lung cancer presence in the particular patient.
ASC followed by computed tomography (CT) scanning is hypothesized to be less costly with
improved prognosis from early detection of disease.
Using a computer-simulated model, a hypothetical cohort of patients at high risk for lung cancer
was screened using ASC as a first step in the screening algorithm. The incremental cost-utility
was determined for 5-year annual screening using ASC and CT compared to CT screening alone
and no screening.
Results show ASC is moderately cost-effective with an incremental cost-utility (compared with
no screening) of $54,923/QALY (2002 CDN$). Using the most favourable assumptions for the
model, the cost-effectiveness improved to $34,388/QALY. Comparatively, screening with CT
alone was a weakly dominated strategy. Sensitivity analyses showed the most influential
parameters to be specificity of the ASC test and prevalence of disease.
Despite certain limitations with the study, a very conservative approach to treatment and costs
was adopted in the model and ASC shows promise as a cost-effective lung cancer screening tool.
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