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Smoking and Lung Cancer

The Facts About Smoking and Lung Cancer


Updated June 06, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Close up of woman lighting cigarette
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By now, most people are aware of the connection between smoking and lung cancer. Yet I still hear the comments; "My uncle smoked for 60 years and never got lung cancer.” “My aunt never smoked, but got lung cancer anyway." What are the facts about cigarette smoking and lung cancer?

The Statistics

Following the 1964 Surgeon General’s report on Smoking and Health, the public became widely aware of the risk of smoking. In that report, it was estimated that smokers had a nine- to ten-fold increased risk of developing lung cancer compared to non-smokers. But we suspected a link between smoking and lung cancer long before that time. Going through my grandparents belongings, I came across an article in Readers Digest, “Cancer by the Carton.” It was dated 1952. We now know that smoking is responsible for 87% of lung cancers in the United States.

Men who smoke are 23 times more likely to develop lung cancer than those who don’t smoke, and women smokers are 13 times more likely to develop the disease than their non-smoking counterparts. The risk of developing lung cancer is directly related to the number of cigarettes smoked, something we calculate using the term “pack-years.”

That said, the majority of lung cancers (over 50%) now occur in former smokers that have quit, and roughly 10% of men and 20% of women with lung cancer have never smoked.

The Culprits

There are more than 50 chemicals in tobacco smoke that are known to cause cancer. Some of the better known carcinogens (cancer causing chemicals) include arsenic, benzene, nickel, and vinyl chloride. Our About.com Guide to Smoking Cessation, Terry Martin, reviews these chemicals in depth in:

Smoking and Lung Cancer Types

The lung cancer types found in people who smoke often differ from those in non-smokers. Small cell lung cancers, which account for roughly 20% of lung cancers, occur almost always in individuals who smoke or have smoked. Non-small cell lung cancers (NSCLC) are the type found more commonly in non-smokers, but the majority of cases still occur in people who have smoked. Historically, people who smoke were more likely to have a form of NSCLC called squamous cell lung cancer, and non-smokers a form called adenocarcinoma. With the switch from unfiltered to filtered cigarettes, adenocarcinomas have become more common in people who smoke.

Does Quitting Help?

It is never too late to quit smoking. If you quit smoking before the age of 30, you can lower your risk to nearly that of a someone who has never smoked. Quitting by age 50, halves your risk of developing the disease. But quitting at any age can reduce your risk of developing lung cancer.

Smoking After a Diagnosis of Lung Cancer

Even if someone has been diagnosed with lung cancer, quitting smoking can make a difference. Quitting smoking with lung cancer can make surgery more successful, treatment more effective, and lowers the risk of dying from another condition, such as another cancer or heart disease. Quitting smoking may also may also improve quality of life after a diagnosis of lung cancer, and studies suggest that individuals who continue to smoke have more moderate to severe pain, than those who are able to put cigarettes aside.

Lung Cancer Screening

In the past, it was thought that performing yearly x-rays might help detect lung cancer at an early stage in people who had smoked, but this is no longer recommended. Studies are now looking at CT screening as a way to detect lung cancer at the earliest stages. If you have a history of smoking, you may wish to discuss the issues about lung cancer screening with your doctor.

Resources for Quitting

If you smoke and need help to quit, talk with your doctor. Our About.com Guide to Smoking Cessation, Terry Martin offers some excellent resources to get you started:
  • Your Quit Smoking Toolbox - Terry provides articles ranging from motivational tips to get you started, to helpful resources to guide you through to success. She also has a very active Quit Smoking Forum where you can share your challenges and victories with support of others 24 hours a day.
  • Quit Smoking 101 - This is a free email course offered by Terry Martin

The Stigma of Lung Cancer

Since smoking is associated with the majority of lung cancers, there is a stigma associated with lung cancer. A stigma that somehow individuals have caused their disease and "deserve" to have cancer. This stigma is damaging and unfair. We don’t confront people who are overweight or sedentary suggesting that they are responsible for illnesses they develop. Regardless of the cause of a cancer, or any condition for the matter, people who are struggling with a chronic illness need our unconditional caring and support.


National Cancer Institute. Fact Sheets. Harms of Smoking and Benefits of Quitting. 01/12/11. http://www.cancer.gov/cancertopics/factsheet/Tobacco/cessation

National Library of Medicine. Profiles in Science. The Reports of the Surgeon General. 1964 Report on Smoking and Health. Accessed 11/07/09. http://profiles.nlm.nih.gov/NN/Views/Exhibit/narrative/smoking.html

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