Lung Cancer: Risk Factors, Diagnosis, and Treatment

Risk Factors

• Cigarette smoking: This accounts for at least 90 percent of cases.
  
• Passive smoking: Epidemiologic evidence suggests that exposure to “secondhand” smoke increases the risk of lung cancer by 20 to 25 percent in nonsmokers.
  
• Occupational hazards: Regular occupational exposure to asbestos, chromium, nickel, benzopyrene, acroleine, nitrous monoxide, hydrogen cyanide, formaldehyde, nicotine, radioactive lead, carbon monoxide, insecticides or pesticides containing arsenic, glass fibers, or coal dust increases workers’ risk of lung cancer.
  
• Family history: Smokers who have a family history of lung cancer have more than 10 times increased risk of developing lung cancer themselves. 
  
• Air pollution: In industrialized areas with high rates of air pollution, the death rate from lung cancer is up to five times greater than in rural, less polluted areas.
  
• Chronic or recurrent respiratory diseases, such as pneumonias, bronchitis, and tuberculosis.
  
• Ionizing radiation exposure, such as X–rays and radon gas.
  
• Diet and nutrition: See Nutritional Considerations.

Diagnosis

• The first step is a medical history and physical examination.
  
• Blood testing is often performed.
  
• Chest X–ray can detect cancers up to two years before symptoms appear. It defines the tumor size and location and can track progression or remission.
  
• Several tests are available to further visualize and define a lung tumor, including CT scan, bronchoscopy, ultrasound, and other tests.
  
• Ultimately, definitive diagnosis requires a biopsy of the tumor.

Treatment

Prevention is clearly the most effective strategy. Smoking cessation is strongly recommended–both for lung cancer patients and their families. Smokers who quit experience a gradual risk reduction over time. When prevention has failed, the following treatment steps apply:

• The primary treatment for most cases of lung cancer is surgery. Surgery may involve removal of part or the entire diseased lung.
  
  In many cases, surgery will not cure the disease. However, it may significantly improve symptoms and prolong survival.
  
• Radiation therapy is usually recommended in early stages of cancer and may be used with or without surgery to remove the tumor. Newer techniques have been developed to improve the effect of the radiation and decrease side effects.
  
  A potential side effect of radiation is severe lung dysfunction (called “irradiated lung”). Symptoms include severe shortness of breath, cough, chest pain, fever, and malaise.
  
• Chemotherapy is the primary treatment for small cell lung cancers, and is used in addition to surgery and radiation for other types of lung cancers.
  
• Additional therapies to address the symptoms of lung cancers include pain medications, sleep medications, cough medicines, and antibiotics.