What is the risk of cancer associated with smoking (tobacco use)?

From the Guidelines

Smoking tobacco is a major modifiable risk factor for developing lung cancer and other cancers, accounting for 85% of all lung cancer-related deaths. The risk of cancer associated with smoking is significant, with approximately 443,000 United States adults dying from smoking-related illnesses each year, and cigarette smoking estimated to cause about 30% of deaths due to cancer 1.

Key Points

• Tobacco smoke contains more than 50 known carcinogens, establishing a firm link between smoking and lung cancer risk 1.
• A dose–response relationship exists between smoking tobacco and the risk of developing lung cancer, with no risk-free level of tobacco exposure 1.
• The relative risk (RR) for lung cancer is approximately 20-fold higher for smokers than for nonsmokers, highlighting the substantial increase in risk associated with smoking 1.
• Cessation of tobacco smoking decreases the risk for lung cancer, although former smokers have a higher risk for lung cancer compared with never-smokers 1.

Cancer Risks Associated with Smoking

• Lung cancer: smokers are at a significantly increased risk, with the RR being approximately 20-fold higher than for nonsmokers 1.
• Other cancers: smoking is also associated with an increased risk of kidney, bladder, pancreatic, gastric, or cervical cancer, or acute myeloid leukemia 1.

Reducing Cancer Risk

• Quitting smoking at any age reduces cancer risk, with benefits beginning within hours of cessation.
• Nicotine replacement therapies, prescription medications, and behavioral counseling can improve success rates for those struggling to quit.

Global Impact

• Globally, experts estimate that deaths from smoking tobacco will increase to 10 million by 2020, emphasizing the need for urgent action to reduce tobacco use 1.

From the Research

Risk of Cancer Associated with Smoking

The risk of cancer associated with smoking is a significant public health concern. Studies have consistently shown that smoking is a major cause of cancer, particularly lung cancer.

• The association between cigarettes and lung cancer has been proven by large cohort studies, with tobacco use being the main cause of 90% of male and 79% of female lung cancers 2.
• Smoking has been identified as a definite cause of cancer at many sites, with 30% of all cancers in the United States being preventable if cigarette smoking were eliminated 3.
• The risk of lung cancer development is 20-40 times higher in lifelong smokers compared to non-smokers, and reducing cigarettes per day may lower the risk of lung cancer compared to continuing to smoke at the same intensity 2, 4.

Types of Cancer Associated with Smoking

Smoking is associated with an increased risk of various types of cancer, including:

• Lung cancer: 90% of deaths from lung cancer are estimated to be due to smoking 2.
• Cervix, pancreas, bladder, kidney, stomach, and hematopoietic tissue cancers: rates of these cancers are increased by 50% to 200% in smokers compared to non-smokers 3.
• Oral cavity, esophagus, and bronchus cancers: these cancers are at the greatest risk of malignancy among smokers due to direct contact with smoke 3.

Reducing the Risk of Cancer

Quitting smoking is the most effective way to reduce the risk of cancer, with the risk of lung cancer decreasing after smoking cessation 2, 4, 5.

• Reducing smoking intensity and the time spent smoking may also lower the risk of lung cancer, although quitting completely is the most effective way to reduce this risk 4.
• Sustained counseling and provision of cessation medication can result in higher quit rates among smokers, particularly those recently diagnosed with cancer 6.