Smoking and cancer

Thanks to years of research, the links between smoking and cancer are now very clear. Smoking is by far the most important preventable cause of cancer in the world. Smoking accounts for one in four UK cancer deaths, and nearly a fifth of all cancer cases.

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 more than four in five 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. 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), pharynx (upper throat), nose and sinuses, oesophagus (food pipe), liver, pancreas,stomach, kidney, bladder, cervix and bowel, as well as one type of ovarian cancer and some types ofleukaemia. There is also some evidence that smoking could increase the risk of breast cancer.

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. Anda 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 more than 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.

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 35,000 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.

Finding it hard to quit? Get involved with Stoptober. Research shows that if you can stop smoking for 28 days, you are five times more likely to stay smokefree, and Stoptober leads smokers through a detailed step-by-step programme to help them achieve this goal.