Malignant lung tumors are one of the common causes of cancer deaths worldwide. A tumor that originates in the lungs is known as primary lung cancer. A tumor that develops in the lungs as a result of the spread of cancer (metastasis) from elsewhere in the body is known as secondary lung cancer.
Smoking is the main cause of primary lung cancer, and passive smoking is a risk factor for nonsmokers. More rarely, primary lung cancer may be caused by toxic chemicals, radon (a radioactive gas), or mineral dusts, such as asbestos. Secondary lung cancer is a common feature of many other types of primary cancer, including breast, colon, prostate, and kidney cancer.
The first and most common symptom of both types of lung cancer is usually a cough.
Other symptoms may include coughing up blood, shortness of breath, and chest pain.
A tumor may also cause pleurisy (inflammation of the membranes surrounding the lungs) or pneumonia.
Primary cancer may also spread to other parts of the body, especially the liver, brain, or bones.
Treatment of primary lung cancer may involve surgery, radiation therapy, chemotherapy, or sometimes newer treatments, such as medications known as biological therapies or laser therapy. Treatment of secondary lung cancer is aimed at the underlying primary cancer.