Most people associate lung cancer with smoking. But you may be surprised to learn that there are 16 different cancers that can be caused by smoking.1 So how does smoking cause cancer throughout the body? How long and how much smoking does it take to cause cancer? And how can quitting smoking reduce your cancer risk – and even improve your outlook if you have been diagnosed with cancer?
Smoking is the biggest preventable cause of cancer
Smoking is by and large the biggest single preventable cause of cancer.2 There, we said it. We're not trying to scare you, but it is important for you to have the facts. And once you have the facts, YOU are in charge of what you'll do with them.
The good news: It's never too late to give up smoking
The good – and very important – news is that it's never too late to give up smoking.1 When you quit, you'll start experiencing some of the health benefits almost immediately.3 From there, the news just gets better and better. Every week, month and year that you stay smoke-free, the health benefits accumulate and the risk of smoking-related diseases, including cancer, decreases.3
So how does smoking cause cancer?
There are over 7000 chemicals in tobacco smoke and 69 of these are known to cause cancer – called carcinogens.1
Every time you take a puff of a cigarette, the chemicals in the smoke enter your bloodstream and through your blood, spread to other parts of your body. This is how smoking can cause cancer in many different parts of your body.2
The main way these chemicals cause cancer is by damaging your DNA, including damaging some of the key genes that protect against cancer.2 Other chemicals in cigarettes, like chromium, make the poisons in cigarettes stick harder to your DNA, increasing the chance of damage.2 Still more chemicals, like arsenic and nickel, interrupt the pathways for repairing DNA.2
How much smoking for how long before this damage adds up to cancer?
There is no safe amount of smoking.4 Research shows that with every 15 cigarettes smoked, there is damage to DNA which could cause cancer in a cell.2 Over a lifetime, smoking just one cigarette a day can cause lung, bladder and pancreatic cancer.4 The higher the number of cigarettes smoked per day and the longer the duration of smoking, the higher the risk of cancer.2,4
How long after giving up smoking does cancer risk reduce?
Your health will start to benefit from quitting within 20 minutes of your last cigarette.3 The health benefits continue over time. Within five years of quitting, the risk of mouth, throat, oesophagus, and bladder cancers are halved.3 And within 10 years of quitting, the risk of dying from lung cancer is about half that of a person who still smokes.3 And remember, the earlier you quit, the greater the benefit.4
What if I have already been diagnosed with cancer? Is it too late to quit?4
It’s never too late to quit smoking. Quitting smoking can improve the outlook for people with cancer. Smokers who quit when they are diagnosed with some cancers may reduce the risk of dying by 30-40%. Longer-term, quitting smoking may reduce the chance of the cancer coming back or a second cancer developing. Quitting smoking also helps the body to respond to and heal from surgery, chemotherapy and other treatments.
What are the 16 cancers caused by smoking?
- Lung cancer
Tobacco smoking is the largest single cause of lung cancer, responsible for about 90% of lung cancers in men and 65% of lung cancers in women. Smokers are 10 times more likely than non-smokers to develop lung cancer. The risk is linked to the age you start smoking, how long you smoke, and the amount you smoke.5
Exposure to secondhand smoke (also called passive smoking) is also a cause of lung cancer.5
- Mouth, throat, nose and sinus cancers6
Cancers of the mouth, throat, nose and sinuses are often called by the general term 'head and neck cancers'. The two main risk factors for these cancers are smoking tobacco and drinking alcohol.
Smokers have about seven times the risk, whereas drinkers have about six times the risk of developing these cancers compared to non-smokers. People who combine heavy smoking and drinking are in dangerous territory with a 35 times increased risk of developing these cancers.
- Bladder cancer7
Smokers have up to three times the risk of developing bladder cancer than non-smokers.
- Kidney cancer8
People who smoke are almost twice as likely to develop kidney cancer than non-smokers. It's thought that about one in three kidney cancers are related to smoking.
- Ureteral cancer
The ureters are the tubes that carry urine from your kidneys to your bladder. Ureteral cancer is uncommon and is closely related to bladder cancer.9 Like bladder and kidney cancer, smoking is one of the risk factors.9
- Oesophageal cancer10
The oesophagus is also known as your food pipe or gullet. It's a long, muscular tube that connects your mouth and throat to your stomach. The exact causes of oesophageal cancer aren't known, but smoking is one of the factors that can increase your risk of this cancer.
- Pancreatic cancer11
The pancreas is a gland that’s part of your digestive system, lying between your stomach and spine. Smokers are two to three times more likely to develop pancreatic cancer than non-smokers.
- Stomach cancer12
The exact causes of stomach cancer aren’t known, but smoking is one of the factors that can increase your risk.
- Primary liver cancer
Primary liver cancer is cancer that starts in the liver13. While most primary liver cancers are related to chronic hepatitis B or C infection, other risk factors include smoking.13
- Cervical cancer
The cervix connects the vagina to the uterus. Most cases of cervical cancer are caused by an infection called human papillomavirus (HPV).14 In women who have HPV, chemicals in tobacco can damage the cells of the cervix and make cancer more likely to develop.14
- Ovarian cancer15
Smoking increases the risk of a type of ovarian tumour called mucinous ovarian cancer. The longer you have smoked, the greater the risk.
- Bowel cancer16
The exact cause of bowel cancer is not known – but we do know that certain lifestyle factors, including smoking, increase the risk.
- Acute myeloid leukaemia (AML)17
Smoking is the only lifestyle factor that’s been proven to increase the risk of this acute form of leukaemia.
Are you ready to reduce your risk?
Reducing your risk of smoking-related cancers can begin today with your decision to quit. And because this is such a momentous decision that you will want to stick with, it makes really good sense to set things in motion by making an appointment to see your doctor.
Your doctor can tell you more about different methods and tools to support quitting, and you’ll be up to 4x more likely to quit successfully with the help of a healthcare professional compared with quitting unaided.18 What are you waiting for?