- • Worsening or chronic cough, shortness of breath,
weight loss, fatigue. More common in patients with chronic obstructive
pulmonary disease (COPD).
- • Dyspnea, hemoptysis, anorexia, many patients are
asymptomatic (with abnormalities detected on thoracic imaging).
- • Chest x-ray or chest computed tomography (CT):
nodule, enlarging mass, persistent/nonresolving infiltrate,
atelectasis, mediastinal or hilar adenopathy, pleural effusion;
patients may present with manifestations of metastatic disease.
- • Histological confirmation of lung cancer on biopsy
specimens (sputum cytology, bronchial biopsies, pleural fluid, lymph
node sampling, needle aspirations).
Lung cancer is the leading cause of cancer death in men and women
in both the United States and the world. More Americans die each
year of lung cancer than of colon, breast, and prostate cancer combined.
The overall 5-year survival of lung cancer is 15% or less
and has only shown minimal improvement over the past 30 years. The
vast majority (85–90%) of cases of lung cancer
are attributable to smoking, and intensive research efforts have
identified hundreds of carcinogens contained in both mainstream
smoke (smoke directly inhaled by the smoker) and sidestream smoke
(smoke released from burning tobacco between puffs plus smoke exhaled
by the smoker). Although risk for lung cancer decreases significantly
after smoking cessation, overall disease risk reduction takes years
and an individual’s risk never returns to that of a never
smoker (never smoker is defined as fewer than 100 cigarettes in
an individual’s lifetime). Historically, 20 pack-years
of tobacco exposure or more has been considered to contain the highest
risk populations. Due to the large number of former smokers, new
cases of lung cancer in the United States are diagnosed more commonly
in former smokers than current smokers.
Other environmental factors can contribute to the development
of lung cancer. Table 41–1 contains a list of
proven and suspected agents that have been implicated in the development
of lung cancer in current, former, and never smokers. Of particular
note, many of these exposures, when coupled with smoking, lead to
exponential increases in the risk of developing lung cancer. For example,
smokers with asbestos exposure have a 50–100 times increased
risk of developing lung cancer.
Environmental Risk Factors for Developing Lung Cancer. |Favorite Table|Download (.pdf)
Environmental Risk Factors for Developing Lung Cancer.
|Passive/environmental tobacco smoke|
|Metals (chromium, arsenic, iron oxide)|
|Industrial (bischloromethyl ether)|
|Polycyclic aromatic hydrocarbons|
|History of tuberculosis|
There are also disease states that are associated with an increased
risk of lung cancer. First, patients who develop COPD [defined
as chronic bronchitis or emphysema with pulmonary function testing
showing at least mild airflow limitation, forced expiratory volume
in is (FEV1) <70% predicted and/or
FEV1/forced vital capacity (FVC) <0.70] secondary
to smoking have been shown to have higher rates of lung cancer.
Ongoing large epidemiological studies have shown that hazard ratios
for the development of lung cancer are the highest in the lowest
quartile of percentage predicted FEV1. There is also a
genetic predisposition to lung cancer as evidenced by increased ...