Lung Cancer Causes and Symptoms

The U.S. National Library of Medicine says that lung cancer is the leading cause of cancer deaths in the United States. Lung cancer occurs when tumors grow on one or both lungs, decreasing the lungs ability to send oxygen to the rest of the body. Multiple factors cause lung cancer, and lung cancer symptoms affect a person's ability to complete daily functions.

Smoking

• Smoking is the leading lung cancer cause for most sufferers. Lungcancer.org states that approximately 87 percent of lung cancer cases involve tobacco smoke. People exposed to secondhand smoke risk developing lung cancer.

Environmental Factors

• The U.S. National Library of Medicine says that lung cancer causes include environmental factors like air pollution, asbestos exposure, radiation and industrial toxins.

Tuberculosis

• Tuberculosis causes lung cancer because this contagious condition scars lung tissue. The U.S. National Library of Medicine says that this bacterial infection primarily affects people with weak immune systems.

Respiratory Symptoms

• Lung cancer symptoms include a variety of respiratory conditions such as persistent, sometimes bloody coughs, shortness of breath, hoarseness, chest pain, mucus buildup and repeated cases of pneumonia and bronchitis.

Pain

• The U.S. National Library of Medicine says that lung cancer symptoms include experiencing pain in other parts of the body. These symptoms include back and shoulder pain from coughing, headaches, joint pain, unexplained bone fractures and swelling around the face and neck.

Unusual Symptoms

• Some lung cancer symptoms do not directly affect the lungs or cause physical discomfort. Lungcancer.org says some of these symptoms include weight loss, loss of appetite, fatigue and memory loss.