ABSTRACT
Lung cancer is the number one cause of death from cancer in the United States. Currently,
there is no official recommendation to screen for lung cancer even in high-risk populations.
Accordingly, we wait for patients to present with symptoms. Only 15-20% of patients
are stage I lung cancer at diagnosis. Past screening trials with chest roentgenogram
and sputum cytology did not show a reduction of lung cancer mortality in the screened
population. Since the completion of those trials in the early 1980s we have learned
that the chest X ray is not sensitive at detecting lesions <2 cm in size, and patients
with chronic obstructive pulmonary disease (COPD) have a 4- to 6-fold increased risk
of lung cancer independent of their smoking history. Recent trials with spiral computed
tomography (CT) scan screening have detected 80-85% of lung cancers while they are
stage I. The problems related to spiral CT screening are the cost and the frequent
detection of benign lesions. Algorithms are being developed to try and prevent unnecessary
biopsies and/or surgery. Sputum cytology is currently the only clinically approved
sputum test for detecting lung cancer. However, in patients with moderate dysplasia
of cytology, the LIFE autofluorescence bronchoscopy system may yield an increased
sensitivity of detecting precancerous or cancerous lesions. More studies are needed
before the LIFE system can be adopted as a standard clinical tool. Currently, investigators
are evaluating the sputum for early lung cancer detection markers. The marker that
is the most developed is the monoclonal antibody to the heterogeneous nuclear ribonucleoprotein
A2/B1 on the sputum epithelial cell surface. Encouraging preliminary results have
been reported and trials are ongoing. The future looks bright for the field of lung
cancer screening.
KEYWORD
Lung cancer - low-dose spiral CT - sputum markers - COPD
