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Essentials of Diagnosis

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  • • 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).

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General Considerations

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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.

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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.

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Table 41–1. Environmental Risk Factors for Developing Lung Cancer.
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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 ...

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