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Does smoking cause non-small cell lung cancer?

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on Nov 5, 2021.

Official answer


Yes, smoking is a major cause non-small cell lung cancer (NSCLC), the most common type of lung cancer. NSCLC accounts for about 85% of all cases of lung cancer. Smoking tobacco contributes to 80% to 90% of all lung cancer deaths.

Lung cancer occurs when normal cells in the lung change into abnormal (unhealthy) cells and grow too rapidly.

There are two types of lung cancer: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). Your doctor will determine which kind you have based on how it looks under the microscope.

  • Lung cancer in smokers can be either NSCLC or SCLC. Lung cancer in non-smokers is usually the NSCLC type.
  • NSCLC is further subdivided into 3 groups based on the type of lung tissue involved: adenocarcinoma, squamous cell carcinoma, and large cell carcinoma. These subtypes are often treated similarly.
  • SCLC tends to occur most frequently in people who are heavy smokers and can be very aggressive and spread rapidly.

Learn more: Which drugs are used to treat NSCLC?

Is lung cancer a common cancer?

Yes, lung cancer is the most common cancer in the world. In the US, lung cancer accounts for about 13% of all cancer diagnoses. It is ‚Äč‚Äčalso the most common cause of cancer deaths in the U.S., but those numbers are declining.

The American Cancer Society estimates that roughly 236,000 new cases of lung cancer (119,000 in men and 117,000 in women) will occur in 2021, with over 131,000 deaths (69,000 in men and 62,000 in women).

Unfortunately, lung cancer is a particularly deadly cancer. According to the American Lung Association, the lung cancer five-year survival rate is 18.6%. This rate is much lower than many other common cancers, such as colon (64.5%), breast (89.6%) and prostate (98.2%) cancer. More than 50% of people with lung cancer die within one year of being diagnosed.

One of the best ways to help prevent lung cancer is to never start smoking. If you smoke now, you should quit. Talk to your doctor about programs to help you with this. In addition, avoid second-hand smoke in your home, work, restaurants and bars.

Related: Smoking Cessation Agents

Besides smoking, what else causes lung cancer?

Smoking is by far the leading cause of lung cancer and leads to a 13 times higher risk for lung cancer than in non-smokers. Cigars and pipe smoking are almost as likely to cause lung cancer as cigarettes.

Other causes of lung cancer besides smoking include:

  • exposure to toxins like radon, asbestos, and some metals like arsenic, beryllium, and uranium
  • exposure to cancer causing chemicals
  • personal or family history of cancer
  • second-hand smoke
  • radiation
  • other diseases such as tuberculosis (TB) and chronic obstructive pulmonary disease (COPD)
  • air pollution, diesel exhaust
  • gene changes that can alter lung cells and cause cancer

Can you get lung cancer if you have never smoked?

You can still get lung cancer if you have never smoked, although it is much less common. Non-smokers are considered to be those who have smoked less than 100-lifetime cigarettes.

  • About 20,000 to 40,000 people, or 10% to 20% of all lung cancers in the U.S. occur in non-smokers.
  • Up to 20% of people who die from lung cancer in the US each year are non-smokers.
  • In the U.S. the overall numbers of lung cancer diagnoses are going down, but the rate of lung cancer in non-smokers is increasing.

Most people who have never smoked get non-small cell lung cancer (NSCLC), with adenocarcinoma being the most common type. These types of cancers often have genetic mutations, but advanced medicines for treatment have been developed that can target these mutations.

Learn More: Clearing The Air: Signs, Symptoms and Treatment Options For Lung Cancer


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