What causes Lung Cancer

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What causes lung cancer?


There are several factors that can contribute to the development of lung cancer. Smoking is the number one cause of lung cancer. While smoking is an important risk factor in developing lung cancer, there are many people with lung cancer who have never smoked. Other factors that contribute to lung cancer include the following:

Exposure to chemicals in the air such as asbestos and radon
Lung diseases that can block airflow to the lungs such as chronic obstructive pulmonary disease (COPD) or tuberculosis

Genetics - people with a relative who had lung cancer are at higher risk for developing lung cancer

Age - lung cancer occurs more often in people over 65 years of age
Cigarette smoke contains at least 43 different carcinogens (cancer-causing chemicals). It has been associated with various cancers including lung, esophagus, mouth, stomach, pancreas, and liver, to name just a few. Smoking accounts for at least 30% of all cancer-related deaths and 87% of lung cancer deaths. Approximately 50% of new lung cancers are diagnosed in former smokers. The risk of lung cancer increases with an increase in the total number of cigarettes smoked, referred to as pack-years (number of packs smoked per day times the number of years smoked). The use of cigar and pipe tobacco also increases the risk of developing cancer, but the risk is not as high as with cigarettes.

Secondhand smoke also contains carcinogens, and each year in the US between 5,000 and 10,000 people are diagnosed with lung cancer resulting from breathing secondhand smoke.

Quitting smoking decreases the risk of developing lung cancer. Ten years after quitting, the risk decreases by half. Although smoking cessation lowers this risk of developing lung cancer, the risk never decreases to the level of people who have never smoked. Recent findings for smokers who have been diagnosed with lung cancer suggest that those who quit smoking during their lung cancer treatment may live longer than those who continue to smoke during treatment.

It’s never too late to quit smoking! If you currently smoke and would like to quit, talk to your doctor about the different options to help you stop smoking.