Cigarette smoking accounts for 85 percent of all lung cancer cases, and smoking more than 25 cigarettes a day increases the risk of getting lung cancer by 25 times compared to a non-smoker. Yet people who have never smoked may also develop the disease.

These include people who have been exposed to frequent cigarette smoke from others (passive smoking). Other causes include exposure to radon — a radioactive gas that comes from uranium in rocks and soils —  and exposure to certain chemicals and substances such as arsenic, asbestos, beryllium, cadmium, coal, coke fumes, silica, nickel and air pollution.

Asbestos accounts for 4 percent of all lung cancer cases. Widely used in the construction industry in the past, asbestos has been banned in many countries, but the United States still allows its use in gaskets, friction products, roofing materials, fireproofing materials and other consumer products.

Previous lung diseases, family history of lung cancer, previous radiotherapy treatments and lowered immunity are other risk factors associated with lung cancer.

How does smoking cause lung cancer?

Cigarette smoke, which damages the cells that line the lungs, contains many carcinogens or cancer-causing substances. This damage in lung cells happens as soon as a person starts smoking. Initially, the body can repair the damage caused by these carcinogens, but upon repeated exposure, the damage grows. With time, lung cells can no longer repair themselves and start acting abnormally, leading to cancer.

Quitting smoking reduces the risk of lung cancer. The sooner one quits, the sooner that risk starts dropping.

How does asbestos cause lung cancer?

The duration and concentration of asbestos exposure plays a key role in lung cancer, say researchers. After asbestos fibers are inhaled, they can sit in the lining of the lungs for years. This causes irritation, which increases cellular damage, leading to cancer. The size of asbestos fibers is linked to the type of lung cancer.

Note: Lung Cancer News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.