What is lung cancer?
Lung cancer is caused by the growth of abnormal cells in the lung. It can start anywhere in the lungs and affect any part of the respiratory system. The change from normal cells into cancerous cells usually happens over a period of years.
What causes lung cancer?
Smoking is the number one cause of lung cancer, accounting for nearly 90 percent of cases. Tobacco and the smoke from tobacco contain many cancer-causing substances, known as carcinogens. Carcinogens damage lung cells and, over time, these damaged cells may develop into lung cancer.
Other causes of lung cancer include exposure to secondhand smoke, asbestos and other industrial carcinogens, or to high concentrations of radon – an odorless gas that is released into the air from the breakdown of uranium in soil and water.
Who gets lung cancer?
Smokers and those exposed to smoking are most at risk of developing lung cancer. It is the leading cause of cancer death for both men and women, killing more people than colon, breast and prostate cancers combined. Nearly 70 percent of people diagnosed with lung cancer are older than 65.
What are the symptoms of lung cancer?
Since most lung cancers do not cause any symptoms until they have spread, only about 15 percent of cases are found in the early stages. When lung cancer is found early, it is often because of a chest x-ray, CT scan or other test that was being done for another reason. When symptoms do occur, the most common warning sign is a cough, which happens when a tumor irritates the lining of the airways or blocks the passage of air.
Other symptoms of lung cancer:
- Constant chest pain, often made worse by deep breathing
- Weight loss and loss of appetite
- Coughing up blood
- Shortness of breath
- Recurring infections, such as bronchitis and pneumonia
- New onset of wheezing
- Swelling of the neck and face
- Hoarseness that lasts more than two weeks
- Fatigue
