Smoking and Lung Cancer

Smoking and Lung Cancer: In the United States, cigarette smoking is linked to about 80% to 90% of lung cancer deaths.

quit smoking

Lung Cancer Risk Factors

About 42% of cancer cases and 45% of cancer deaths in the United States are linked to modifiable risk factors and thus could be preventable.

There is strong evidence that lifestyle factors impact cancer risk in a variety of malignancies, including increased risk of lung, colorectal, prostate, and breast cancer. With regards to smoking, secondhand tobacco smoke and smokeless cigarettes are prime risk factors for lung cancer as well as several other cancers.

Lung cancer is the second most common cancer in both men and women and the leading cause of cancer death in the US.

Smokers have an estimated 25-fold increased risk of developing lung cancer as compared with never smokers.

On average, people who smoke die about 10 years earlier than people who have never smoked. Those numbers are frightening!

Non-small cell lung cancer is the most common type of lung cancer. It grows and spreads more slowly than small cell lung cancer. The second most common type is small cell lung cancer, which is almost always related to cigarette smoking. It is a fast-growing cancer that spreads much more quickly (metastasizes) than other types of lung cancer.


In addition to the lungs, smoking tobacco products (including cigarettes and cigars) can cause cancer almost anywhere in your body, including in the mouth, throat, bladder, colon and stomach. Tobacco products such as dipping and chewing tobacco are also linked to cancer including cancers of the esophagus, mouth and throat, and pancreas. The newer electronic cigarettes produce an aerosol by heating a liquid that usually contains nicotine, so there is risk associated with it as well. Currently, there is significant research being conducted to understand the health risks of e-cigarettes. Secondhand smoke is a mixture of 2 forms of smoke that come from burning tobacco called mainstream smoke and sidestream smoke. Non-smokers who breathe in secondhand smoke take in nicotine and toxic chemicals the same way people who smoke do. Secondhand smoke causes lung cancer in people who have never smoked. A family history of lung cancer increases the risk for the disease in both smokers and never-smokers. The majority of people with lung cancer usually do not have symptoms until the disease has progressed. Epidemiological cancer research shows the most common symptoms are:

  • A cough that does not go away or gets worse

  • Coughing up blood or rust-colored spit

  • Chest pain that is often worse with deep breathing, coughing, or laughing

  • Hoarseness

  • Loss of appetite

  • Unexplained weight loss

  • Shortness of breath

  • Feeling tired or weak

  • Infections such as bronchitis and pneumonia that do not go away or keep coming back

  • New onset of wheezing


It is important to know that other conditions or diseases can also cause these symptoms. If you're experiencing any of these symptoms, speak with your primary care physician or your cancer care team, who can help diagnose what is causing them.


One thing to note is that no matter how long you have smoked, quitting can reduce your risk for cancer and other chronic diseases.

Smoking and Lung Cancer

10 years after smoking cessation, the lung cancer death rate of a former smoker is half of that of a current smoker. It is even more remarkable when you consider all the other positive health effects of quitting smoking:

  • A few days after quitting, the carbon monoxide level in your blood drops to normal.

  • A few weeks to a month later, your circulation improves and your lung function increases.

  • A few months later, chronic coughing and shortness of breath decreases. Tiny hair-like structures that move mucus out of the lungs start to regain normal function, increasing their ability to balance mucus production and clearance, clean the lungs, and decrease the risk of infection.

  • A couple of years later, your risk of heart attack drops by half.

  • 5 years later your risk of a stroke is at the level of a non-smoker.

  • 10 years after quitting, your risk of cancers of the mouth and throat is cut in half.

  • 10 to 15 years later, your risk of lung cancer is about half that of a person who is still smoking.

As a bonus, quitting smoking also reduces the chances of impotence, having difficulty getting pregnant, having premature births, babies with low birth weights, and miscarriage.

Must Read : Alcohol and Cancer Risk

Lung cancer screening is advised once a year for patients who:

  • Have been smoking for twenty years or more, and

  • Currently smoke or have quit smoking in the last fifteen years, and

  • Are in the age group ranging from fifty to eighty.

For lung cancer screening, low-dose computed tomography (LDCT) is used. An X-ray machine utilises a low dose (volume) of radioactivity to create high-resolution images of your lungs through an LDCT scan. If lung cancer is discovered, more tests and scans are performed to determine the extent of the disease. This is referred to as staging. The kind and stage of lung cancer determines the therapy options available to you.

Non-small cell lung cancer can be treated with a combination of options including surgery, chemotherapy, radiotherapy, targeted drug therapy and immunotherapy. If you smoke, one of the most important things you can do to be ready for treatment is to try and quit smoking. Several studies have shown that patients who stop smoking after a diagnosis of lung cancer tend to have better outcomes than those who don’t.

Small cell lung cancer is usually staged as either limited or extensive. In most cases, small cell lung cancer has already spread by the time it is found, so chemotherapy is usually the main type of treatment. In cases of extensive disease, chemotherapy and immunotherapy are part of the treatment options. As in the case of non-small cell lung cancer, patients who stop smoking after a diagnosis of lung cancer tend to have better outcomes than those who don’t.

Once you are diagnosed with lung cancer, getting the appropriate standard of care treatment and being aware and prepared for treatment-related side effects is the right way to proceed. Make an effort to maintain your health. Some cancer survivors may hold themselves responsible for their illness or believe that others hold them responsible. Feelings of blame or stigma are common among lung cancer survivors. Talking to a trained mental health professional as part of your cancer care team about your concerns and experiences may be beneficial. Sharing your journey with other cancer survivors or listening to their experiences may also be therapeutic.

It is worth noting that 17% and 6% of patients with non–small-cell and small-cell lung cancer, respectively, have survival rates longer than 5 years. Guidance to optimize their quality of life, addressing their needs from physical, psychological, and social perspectives wherever they are in the cancer diagnosis continuum should always be part of the survivorship plan for all lung cancer patients.


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DOI: 10.1158/0008-5472.CAN-19-2348