Tobacco, smoking and cancer risk

This page was reviewed under our medical and editorial policy by

Cary Presant, MD, Medical Oncologist, City of Hope | West Covina, CA

This page was updated on June 5, 2023.

One of the most important ways to prevent cancer is to avoid tobacco products of any kind. Tobacco use is one of the top causes of cancer and of cancer death, according to the National Cancer Institute (NCI). Smoking tobacco and using smokeless tobacco may cause cancer. Quitting smoking and use of other tobacco products may reduce the overall cancer risk.

What are tobacco products?

Tobacco products include cigarettes, cigars, pipe tobacco, chewing tobacco, snuff, snus, hookah tobacco and more. In 2019, almost 14 percent of U.S. adults smoked cigarettes. Electronic cigarettes (e-cigs) and vape products are also classified as tobacco products by the U.S. Food and Drug Administration (FDA).

The worldwide health effects of tobacco products are enormous. Globally, tobacco use causes about 7 million deaths per year. In the United States, smoking is the leading cause of preventable death, according to the U.S. Centers for Disease Control and Prevention.

Smoking may lead to the health conditions listed below.

  • Cancer
  • Heart disease
  • Stroke
  • Chronic obstructive pulmonary disease (COPD)
  • Emphysema
  • Chronic bronchitis
  • Other lung diseases and infections, such as tuberculosis and pneumonia
  • Diabetes
  • Osteoporosis
  • Rheumatoid arthritis
  • Macular degeneration
  • Cataracts
  • Erectile dysfunction
  • Fertility issues

In addition, smoking during pregnancy may lead to complications for both the woman and baby. It also may worsen symptoms for asthma patients.

Smoking and cancer

Smoking is the cause of most lung cancers, and is linked to several other cancer types as well.

In addition, non-smokers may die from secondhand and thirdhand smoke, due to the cancer-causing substances that can be breathed in by being around someone smoking, or that are left behind on fabric or other surfaces where someone has smoked. 

How many years of smoking causes cancer?

No amount or frequency of smoking is considered safe. In fact, even people who smoke less than one cigarette daily have an increased risk for developing cancer compared to never-smokers. Even so-called “light” or “low-tar” cigarettes pose a risk, research shows.

Quitting smoking is the most significant way for smokers to lower cancer risk, and may also provide other health benefits, such as reducing the risk for developing cardiovascular disease, stroke, aortic aneurysm, heart failure and early death.

Learn more about how smoking causes cancer.

Does marijuana cause cancer?

Smoking marijuana, also known as pot, weed or cannabis, introduces carcinogenic substances to the lungs. Studies indicate that light or moderate weed smoking is not believed to increase the risk for developing lung cancer, although heavy marijuana use may raise risk.

Smoking weed may carry other risks, such as raising the risk for developing lung infections.

Does vaping cause cancer?

The harmful health effects are more well-known for smoking tobacco than for products such as e-cigarettes and vape devices. Smoking tobacco has been around for much longer, and there are still many unknowns about the ingredients used in these newer products.

Still, research suggests that the aerosols created by e-cigarettes and vape products may contain harmful chemicals, such as diacetyl, formaldehyde and other volatile organic compounds (VOCs). These are the same cancer-causing chemicals found in cigarette smoke, but they’re present in lower amounts.

Public health authorities recommend avoiding e-cigarettes and vape products. They contain varying amounts of nicotine and may cause physical dependence. There are no testing requirements, which means there’s no way to know how safe every product is and what chemicals may be lurking inside.

How does tobacco cause cancer?

Cigarette smoke contains at least 69 different carcinogens (substances known to cause cancer), according to the NCI. These chemicals, which include hazardous gases and metals, arsenic and more, cause changes in the cells that may lead to cancer. The carcinogens in tobacco smoke may also pose a risk to others who are exposed to it through secondhand smoke.

Smokeless tobacco, like chewing tobacco, snuff, snus and other dissolvable products, also contain carcinogens that may be absorbed through the tissue of the mouth. While they’re associated with fewer deaths than smoking tobacco, these addictive products may still lead to cancer in the parts of the body listed below.

It also contributes to acute myeloid leukemia, a condition in which too many immature white blood cells are found in the bone marrow and blood.

Remember, there’s no “safe” level of tobacco use. While it may be tough to quit tobacco products, doing so may greatly reduce the risk for developing cancer, cancer death and other severe diseases.

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