Does Smoking Cause Cancer?

The connection between smoking cigarettes and cancer has long been proven. Smoking cigarettes is the leading cause of preventable disease, disability, and death in the United States, and leads to 480,000 deaths in the U.S. each year. 

The Centers for Disease Control and Prevention (CDC) estimated that in 2019 approximately 34.1 million American adults were regular cigarette smokers, and more than 16 million were living with a smoking-related disease. Researchers defined a “current smoker” as someone who reported smoking at least 100 cigarettes in their lifetime or who reported smoking some days or every day.

Fortunately, the prevalence of smokers has gone down in recent years. In 2005, about 20.9% of American adults smoked, and in 2019 that number dropped to 14%. 

Smoking Types and Impact on the Lungs

Verywell / Danie Drankwalter

While the link between cigarettes and cancer is well understood, there are other types of smoking that have not received the same amount of research. This article will describe the different types of smoking and how they are related to an increased risk for several different types of cancer. 

Smoking and Cancer

Smoking raises the risk of cancer because it damages the lungs and other bodily tissues. People who smoke experience damage to their airways and small air sacs in the lungs. Smoking is also associated with heart disease because it leads to damage to the blood vessels and the heart itself. 


Smoking tobacco is dangerous to our health because it raises the risk of cancer and other chronic health problems. It’s estimated that tobacco use causes one in five deaths in the United States, and we know that people who smoke die on average 10 years earlier than those who don’t.

Experts believe that smoking cigarettes or cigars causes about 20% of all cancers in the United States and is to blame for 30% of all cancer deaths. According to the American Cancer Society, about 80% of all lung cancers in the United States are caused by smoking. Lung cancer is still the leading cause of death in both men and women. 

Smoking cigarettes has been linked to an increased risk for the following cancers:


It is unclear if smoking marijuana raises the risk of lung cancer. However, we know that smoking marijuana causes lung damage. Research shows that marijuana smoking leads to inflammation in the airways. This inflammation can cause symptoms of chronic bronchitis and other respiratory problems. 

It is also possible that smoking marijuana affects the body’s immune system. Because marijuana has immune-suppressing properties, it may lead to an increased risk of lung infections like pneumonia

Marijuana smoke contains many of the same cancer-causing chemicals as cigarette smoke. It even has 50% more benzopyrene and 75% more benzanthracene than cigarette smoke. 

While marijuana is typically smoked less frequently than cigarettes, its smoke is usually inhaled deeper into the lungs and held for longer than cigarette smoke. Because of the different way it is smoked, marijuana smoke leads to four times the tar buildup in the lungs as cigarette smoke. 


E-cigarettes are vaping devices that produce an aerosol by heating a liquid that contains nicotine. The risks associated with e-cigarettes are not as well understood as those of cigarettes. However, the information that is available indicates that e-cigarettes are very dangerous to our health. 

E-cigarettes are known to irritate the tissue in the lungs and cause damage to the heart. Like traditional cigarettes, e-cigarettes contain nicotine, which is known to be addictive. It may also harm the brain development of children and teenagers. 

Individuals who regularly vape have reported chronic symptoms including:

It is important to remember that e-cigarettes contain many of the same cancer-causing chemicals found in cigarettes. 


The most common signs and symptoms of lung cancer include:

  • A persistent cough
  • Coughing up blood or blood-tinged sputum
  • Chest pain
  • Loss of appetite
  • Unintended weight loss
  • Shortness of breath
  • Fatigue 
  • Respiratory infections that don’t improve
  • New-onset wheezing 

Early Signs

Lung cancer does not always cause symptoms in the early stages. Often, symptoms present once cancer has begun to spread. As soon as you develop any signs or symptoms of lung cancer, it’s important to see your doctor right away. 

Lung Cancer Types

Lung cancer develops in the lung tissues and usually in the lining of the airways. The two most common types of lung cancer are small cell lung cancer and non-small cell lung cancer. Non-small cell lung cancer makes up about 80% to 85% of all lung cancer cases. 

Small Cell Lung Cancer (SCLC)

Small cell lung cancer makes up about 13% of all lung cancer cases. It can be classified into one of two stages:

  • Limited stage: Cancer can be found in one area of the chest. It may have spread to the nearby lymph nodes. Treatment usually involves radiation therapy to one area of the body. If cancer has not spread to the lymph nodes yet, your medical team will most likely recommend surgery and chemotherapy. If cancer has reached the lymph nodes, radiation therapy is recommended as well. 
  • Extensive stage: Cancer has spread to the entire lung and may have also spread to the other lung, the lymph nodes, the fluids surrounding the lungs, or distant areas of the body. Treatment usually includes chemotherapy and immunotherapy. The cancer has spread too far for surgery or radiation therapy to be helpful. 

Non-Small Cell Lung Cancer (NSCLC)

Non-small cell lung cancer is the most common type of lung cancer, and smoking is the major risk factor. Types of non-small cell lung cancer include squamous cell carcinoma, large cell carcinoma, and adenocarcinoma. 

Stages of non-small cell lung cancer range from stage 0, also known as carcinoma in situ, to stage 4. Typically, the lower the number of the stage, the less the cancer has spread throughout the body and the easier it is to treat. 

Lung Cancer Stages

Lung cancer staging is a tool used to determine how advanced an individual’s lung cancer is. The lung cancer staging shows how far cancer cells have spread beyond the lungs and helps to develop the most effective treatment plan. 

Stage 1

In stage 1 lung cancer, the abnormal cells in the lining of the lungs have turned into cancer. Treatment for stage 1 non-small cell lung cancer usually starts with surgery to remove the cancerous portion of the lung. Your surgeon may recommend taking out the entire lobe, known as a lobectomy, or a smaller portion. During surgery, the surgeon will likely remove nearby lymph nodes to check them for cancer as well. 

Stage 2

In stage 2 lung cancer, cancer cells have begun to spread to nearby tissues. Treatment for stage 2 non-small lung cancer will depend on the exact size of the tumor and how far cancer cells have spread. The treatment plan usually starts with surgery to remove a lobe or the entire lung (pneumonectomy). Nearby lymph nodes are usually removed as well and then tested for cancer cells. After surgery, your medical team may recommend chemotherapy or radiation therapy to kill any remaining cancer cells. 

Stage 3

In stage 3 non-small cell lung cancer, the tumor has grown and possibly reached the lymph nodes. Treatment for stage 3 non-small cell lung cancer usually includes a combination of surgery, chemotherapy, and radiation therapy.

Stage 4

In the final stage, stage 4 non-small cell lung cancer, cancer cells have spread to distant tissues of the body such as the opposite lung, bones, brain, liver, or kidney. Stage 4 non-small cell lung cancer is difficult to treat and cure because of how advanced it is. Depending on how healthy you are otherwise, treatment may include surgery, chemotherapy, radiation therapy, targeted therapy, and immunotherapy. 

Other Risk Factors

In addition to tobacco smoke, other known risk factors for lung cancer include:

  • Radon: Radon is a naturally occurring radioactive gas that you cannot see, smell, or taste. It’s believed to be the second leading cause of lung cancer in people who do not smoke. 
  • Asbestos: Asbestos is a group of naturally occurring minerals that are most likely to be found in mines, mills, textile plants, shipyards, and places where people work with insulation. Exposure to these minerals at work raises your risk for lung cancer, especially if you also smoke.
  • Radiation: Receiving radiation to your chest is a risk factor for lung cancer, especially if you also smoke. People who may have a history of chest radiation include those treated for Hodgkin disease or breast cancer.
  • Air pollution: It’s estimated that air pollution is to blame for about 5% of all lung cancer deaths worldwide. This risk factor is difficult to address because we as individuals usually do not have control over the quality of the air we breathe. 


The best way to prevent lung cancer is to avoid the risk factors that lead to it. Ways to prevent lung cancer include:

  • Quit smoking.
  • Avoid radon exposure.
  • Protect yourself against asbestos exposure.
  • Eat a healthy diet.


The treatment for lung cancer is individual and depends on several factors, including the stage of cancer, how advanced it is, and your overall health. Many treatment plans include surgery, radiation therapy, chemotherapy, immunotherapy, and targeted therapies. 


Smoking cigarettes is the leading cause of lung cancer and lung cancer deaths. Smoking marijuana and e-cigarettes is known to damage the lungs but has not been linked to an increased risk for lung cancer. 

Symptoms of lung cancer include a persistent cough, chest pain, coughing up blood, loss of appetite, shortness of breath, and fatigue. Treatment options include surgery, radiation, chemotherapy, immunotherapy, and targeted therapies. 

A Word From Verywell

The link between smoking cigarettes and cancer is well established, but that does not mean that quitting smoking is easy. If you have decided to reduce or eliminate your smoking habit, talk with your healthcare provider about resources in your area. It’s important to remember that while there is currently no proven link between marijuana smoke or e-cigarette smoke and cancer, all types of smoking cause damage to your lungs and raise your risk for chronic health problems. 

Frequently Asked Questions

  • How many cigarettes can you have in a day?

    There is no known number of cigarettes that you can safely consume in a day. However, reducing the number of cigarettes that you currently smoke each day is still beneficial to your health. 

  • How many cigarettes come in a pack?

    Most packs contain 20 cigarettes. 

  • Can you live with one lung?

    Yes, it is possible to live with one lung. For most people, one lung is able to provide enough oxygen for the body. However, if the one lung is damaged, it may not be able to keep up with the body’s needs. 

19 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention. Current cigarette smoking among adults in the United States. Updated December 10, 2020.

  2. Centers for Disease Control and Prevention. Tobacco-Related Mortality. Updated April 28, 2020.

  3. American Cancer Society. Health risks of smoking tobacco. Updated October 28, 2020.

  4. National Institute on Drug Access. What are marijuana's effects on lung health? Updated July 2020.

  5. American Lung Association. Marijuana and lung health. Updated December 17, 2020.

  6. American Cancer Society. What do we know about E-cigarettes? Updated September 9, 2020. 

  7. American Cancer Society. Health risks of E-cigarettes. Updated October 28, 2020.

  8. American Cancer Society. Lung cancer signs & symptoms. Updated October 1, 2019. 

  9. American Lung Association. Lung cancer basics. Updated August 30, 2021.

  10. American Cancer Society. Non-small cell lung cancer staging. Updated October 1, 2019.

  11. American Cancer Society. Lung cancer statistics | How common is lung cancer? Updated January 12, 2021.

  12. American Cancer Society. Lung cancer treatment by stage. Updated March 3, 2021. 

  13. Cancer Treatment Centers of America. Understand how lung cancer is staged and graded

  14. National Cancer Institute. Definition of stage IIB non-small cell lung cancer. Updated July 15, 2021. 

  15. American Cancer Society. Lung cancer risk factors. Updated October 1, 2019.

  16. American Lung Association. Lung cancer causes & risk factors. Updated October 4, 2021. 

  17. American Cancer Society. Lung cancer prevention. Updated October 1, 2019.

  18. Centers for Disease Control and Prevention. How is lung cancer diagnosed and treated? Updated October 18, 2021.

  19. Johns Hopkins Medicine. Pneumonectomy.

By Carrie Madormo, RN, MPH
Carrie Madormo, RN, MPH, is a health writer with over a decade of experience working as a registered nurse. She has practiced in a variety of settings including pediatrics, oncology, chronic pain, and public health.