- What is lung cancer?
- What causes lung cancer, and who gets it?
- How does lung cancer develop, and how fast does it grow?
- What are the symptoms of lung cancer?
What is lung cancer?
Cancer is the uncontrolled growth of abnormal cells, which crowd out and destroy healthy tissue. Lung cancer occurs in the breathing tubes or in the lung tissues. Lung cancer is the most common cancer-related cause of death among men and women. In over 80% of the cases, this disease might have been preventable.
What causes lung cancer, and who gets it?
The major cause of lung cancer is smoking. The average patient is a man or a woman between 50 and 70 years who has smoked for many years. In patients who never smoked, 30% of lung cancers are caused by passive smoke or from smoke inhaled from other people's cigarettes (secondhand smoke). If a person stops smoking, the risk of cancer decreases steadily each year as normal cells replace abnormal cells.
Other causes of lung cancer are chemicals, such as asbestos, radon, uranium, arsenic and certain petroleum products. Exposure to these chemicals in combination with cigarette smoking sharply increases the risks of developing cancer.
Heredity or family history is also linked with development of lung cancer. Studies have shown that blood relatives of lung cancer patients have increased risk of developing the disease.
How does lung cancer develop, and how fast does it grow?
Researchers and scientists think that lung cancer develops slowly. They believe that 20 or more years pass from the time a person starts inhaling the cancer-producing substance and the time lung cancer actually develops. However, changes in the lung begin almost immediately upon exposure to the carcinogens or cancer-causing substances. With continued exposure, more abnormal cells appear that may be on their way to developing cancer cells.
What are the symptoms of lung cancer?
The symptoms depend on several factors. If the tumor is located in one of the breathing tubes (trachea or bronchus), it can irritate the lining of the tube and cause coughing. The tumor may bleed and cause the person to cough up blood. If the tumor grows larger, it can gradually fill the tube and cause shortness of breath, repeated lung infections or pneumonia.
A tumor located in the lung tissue may not produce any symptoms until it grows larger. The first symptom might be chest pain from the tumor growing into the lining of the lungs, the chest wall or the ribs.
Other symptoms may include hoarseness, weight loss, wheezing and fever without a known reason.
The lungs are rich in blood vessels and lymph vessels. Cancer cells may be carried by these vessels to other parts of the body. These cells may then be deposited in other organs, a process called metastasis. If deposited in the brain, the person may have persistent headaches, dizziness, changes in vision and gait. If it spreads to the bones, the person might experience bone pain. The corresponding symptoms will vary depending on where the cancer cells spread and deposit.