Smoking and Cancer
Most people are aware that smoking can cause lung cancer. But smoking is a cause of a number of other illnesses, including:
- Head & neck cancers (mouth, nasal cavity, throat, voice box)
- Cancer of the esophagus (tube from the mouth to stomach)
- Stomach cancer
- Pancreatic cancer
- Liver cancer
- Bladder cancer
- Kidney cancer
- Cervical cancer
- Emphysema and COPD (chronic obstructive pulmonary disease)
- Heart disease and peripheral vascular disease (poor circulation)
In addition, smoking affects the health of those around you through second hand smoke exposure. Children are particularly susceptible to the health effects of second hand smoke.
How does tobacco cause cancer?
Tobacco and tobacco smoke cause cancer because they contain many chemicals that are known carcinogens (cancer causing agents). Cigarettes, cigars, chewing and pipe tobacco are made from dried tobacco leaves, as well as ingredients added for flavor and other reasons, including making smoking more pleasant. More than 7,000 different chemicals have been found in tobacco and tobacco smoke -- among them are more than 60 known to cause cancer.
Some of the substances found in tobacco smoke include: ammonia, arsenic, benzene (like that found in pesticides and gasoline), cyanide, formaldehyde, tar, and carbon monoxide. Similar substances are found in smokeless tobacco, including Polonium 210 (nuclear waste), cadmium (used in car batteries), lead (which causes nerve poison), nitrosamines, arsenic, and cyanide.
The chemicals in tobacco and tobacco smoke cause damage in the most basic level of our bodies, the cells and genes. Normally, the body has systems that regulate cell growth, repair and death. The genetic damage caused by smoking causes this to malfunction, leading to uncontrolled cell growth. This uncontrolled growth can lead to the formation of tumors. These tumors can grow and spread throughout the body because they are not detected or repaired by the body's normal monitoring systems.
Estimating your risk of lung cancer in numbers
Many current and former smokers want to know their risk of developing lung cancer in numbers. For example, some people want information such as "I have a 10% chance of developing the disease." Assigning a number to risk is very complicated and is often hard to interpret- while one person may think 10% is a high chance, another thinks that is a relatively low number.And for the person who is in that 10% and develops the cancer, the number is meaningless. Remember that statistics like these are numbers based on large groups of people. It can be difficult to translate what that means for any one individual. In other words, don't let the number convince you that it is okay to continue smoking.
If you are still interested in knowing some numbers, researchers at Memorial Sloan Kettering Cancer Center have developed an online tool that estimates risk of lung cancer in numbers for people between 50 and 75 years old who have smoked at least 25 years, though they can be current or former smokers. Remember this tool only considers lung cancer risk and not risk of the 12 other types of cancer or other health conditions that smoking causes.
If you don't fall into that tool's population, you can talk with your doctor about your risk. Calculating a risk is very complicated and some researchers have spent entire careers trying to quantify an individual smoker's risk. Risk calculation takes into account the amount smoked, over what time period and can include other parts of your health history that can increase your risk (asbestos exposure, COPD).
Risk of Other Types of Cancer
There is much less research into the risk for former smokers and other types of cancer. Unfortunately, quitting tobacco cannot completely erase the damage done from previous smoking. However, the risk of other cancers decreases as time passes without tobacco.
Is there a benefit to quitting smoking?
Absolutely! No matter how long or how much you have smoked, quitting reduces your risk of cancer and other smoking related disease. Quitting is rarely easy. Talk with your healthcare provider for help in making a quit plan. Use the links below to learn more about smoking’s health effects and quitting.
You should always be honest with healthcare providers about your smoking history and be aware of the risks associated with this history.
Inform your healthcare provider if you have any of the following symptoms:
- Any change in a cough (for example, you cough up more phlegm or mucus than usual)
- A new cough
- Coughing up blood
- Trouble breathing
- Chest pain
- Loss of appetite
- Weight loss
- Feeling tired all the time (fatigue)
- Frequent lung or respiratory infections (like pneumonia or bronchitis)
- Development of sores or white patches in your mouth.