Cancer Research UK : Smoking and cancer

Smoking and cancer

Smoking is the single biggest cause of cancer in the world.

Thanks to years of research, the links between smoking and cancer are now very clear. Smoking is the single biggest cause of cancer in the world, and accounts for one in four UK cancer deaths.

In the UK, smoking kills five times more people than road accidents, overdoses, murder, suicide and HIV all put together.

Which cancers are caused by smoking?

Smoking causes nine in ten cases of lung cancer. Lung cancer has one of the lowest survival rates of all cancers, and is the most common cause of cancer death in the UK.

Smoking affects the risk of over a dozen cancer.s

The good news is that most of these deaths are preventable, by giving up smoking in time.

Smoking also increases the risk of over a dozen other cancers including cancers of the mouth, larynx (voice box), oesophagus (food pipe), liver, pancreas, stomach, kidney, bladder and cervix, as well as some types of leukaemia.

Not all smokers get cancer. Why?

You may know someone who smoked all their lives but lived to a ripe old age. Or you may know someone who never smoked but got cancer anyway. Does this mean that smoking doesn’t really cause cancer?

Not at all. Years of research have proven that smoking causes cancer. But this doesn’t mean that all smokers will definitely get cancer or that all non-smokers won’t. It means that smoking greatly increases the risk of this disease. Smokers are, on average, much more likely to get cancer than non-smokers.

In a similar way, we can say that eating sugary foods is a cause of tooth decay. This doesn’t mean that all children who eat sugary foods will end up with decayed teeth. It means that, on average, children who eat lots of sugary foods are more likely to develop tooth decay than those who avoid such foods.

The fact is that half of all smokers eventually die from cancer, or other smoking-related illnesses. And a quarter of smokers die in middle age, between 35 and 69.

Our How do we know? page has more information on the evidence linking smoking to cancer.

How does smoking cause cancer?

Tobacco smoke contains about 70 different cancer-causing substances. When you inhale smoke, these chemicals enter your lungs and spread around the rest of your body.

Scientists have shown that these chemicals can damage DNA and change important genes. This causes cancer by making your cells grow and multiply out of control.

Smoking and other diseases

Smoking can also cause heart disease, stroke and chronic lung diseases like bronchitis and emphysema. Smokers are two to three times more likely to have a heart attack than non-smokers. And for women, smoking whilst taking the Pill greatly increases your risk of having a heart attack.

Giving up makes a difference

Thanks to research, health campaigns and new policies, the number of smokers in the UK has halved in the last 50 years. Because of this, the number of people who die from lung cancer has also halved. Clearly, giving up smoking saves lives.

But there is still a long way to go. Lung cancer is still the second most common type of cancer in the UK and kills over 33,000 people every year. And there are signs that the number of people who are quitting is starting to match the number who are taking it up.

If you are a smoker, giving up smoking is the best present you can give yourself. There are many techniques you can try to help you join the increasing numbers of smokers who are quitting for good. You can find more advice on quitting in this section.

Giving up smoking can reduce your risk of cancer, heart disease, stroke and many other conditions.

Get sponsored to quit smoking

Encourage your friends and family to support you in your attempt to quit smoking by sponsoring you.

Find out more about smoking

Find out the truth behind some smoking myths in our Common questions page, including the effects of roll-ups, light cigarettes, exercise, air pollution and more.
Tobacco contains several cancer-causing chemicals, and the addictive drug nicotine. Have you ever wondered about exactly What’s in a cigarette?
Read about the scientific evidence that links smoking to cancer, in our How do we know? page.
Children are especially vulnerable to the chemicals in tobacco and to tobacco advertising. Read about protecting your children from tobacco on our Children and smoking page.
Second-hand smoke, or passive smoke, kills over 10,000 people in the UK every year. Find out about the dangers of second-hand smoke and what Cancer Research UK is doing about it.
Smokeless tobacco (including snuff and chewing tobacco) can cause mouth cancer. Read about the risks in our smokeless tobacco page.

Get help with quitting

Understanding why you smoke is one of the first steps to giving up. Find out more about why people smoke and the addictive effects of nicotine.
There are many good reasons to quit smoking, including better health, saving money and looking younger. Read about these and other reasons to quit.
Cutting down the amount you smoke won’t greatly improve your health. You are better off stopping altogether but this can be hard. In our Giving up page, you can find advice on quitting, what help is available, and how to control withdrawal symptoms.