What is lung cancer and how is it caused?

Your body is made up of many different types of cells. Cancer, including lung cancer, is caused by cells growing out of control. These cancer cells start to get bigger and grow to form a lump. This lump is called a tumour.

Lung cancer is one of the most common types of cancer. There are around 48,500 new lung cancer cases in the UK every year.

More than 4 in 10 cases of lung cancer are diagnosed in people over the age of 75.

Cancer that begins in the lungs is known as primary lung cancer. Cancer that spreads to the lungs from other parts of the body is known as secondary lung cancer.

There are different types of lung cancer:

• Non-small cell lung cancer (NSCLC): This is the most common kind of lung cancer. There are three common types of non-small cell lung cancer: adenocarcinoma, squamous cell carcinoma and large cell carcinoma. 
• Small cell lung cancer (SCLC): This is much less common. It usually spreads more quickly and is often at an advanced stage when it’s diagnosed.
• Mesothelioma: This is a cancer of the lining of the lung (the pleura) and is often linked with asbestos exposure, commonly through work

There are many different risks linked with getting lung cancer. However, it’s important to remember that being exposed to these risks doesn’t mean you’ll definitely get lung cancer.  

Smoking cigarettes

Smoking cigarettes is the biggest cause of lung cancer. Around 70% of lung cancer cases are linked to smoking cigarettes. Breathing in other people’s smoke (passive smoking) can also increase your risk of getting lung cancer.

Cigarettes are made up of harmful chemicals. These chemicals damage the cells in your lungs which can cause cancer.  

Your risk of getting lung cancer increases with the number of cigarettes you’ve smoked and the number of years you’ve been smoking. Your risk of lung cancer gets lower over time if you stop smoking. After 10 years of quitting, your risk of lung cancer falls to half that of a smoker.

Ask your healthcare professional or pharmacist for help to stop smoking. You’re around three times more likely to quit with help from support services and medication. We also have more support on stopping smoking.

Environmental and workplace risks  

There are dangerous materials and gases in some workplaces, such as asbestos, diesel engine fumes, and silica. Exposure to these materials and gases can increase the risk of getting lung cancer.  

Living or working in an area with high radon levels may also increase your risk of getting lung cancer. The risk is higher if you smoke or have smoked. Find out more about radon and asbestos.

Air pollution  

Air pollution harms our lungs. Breathing in air pollution over a long period of time increases the risk of getting lung cancer.  Around 10% of lung cancer cases in the UK are linked to outdoor air pollution.  

A recent study by Cancer Research UK found out how air pollution can cause lung cancer in people who have never smoked. Researchers found that inflammation in the lungs caused by air pollution can wake up normally inactive cells. These cells can become cancer. Hopefully, this research will help us find ways to prevent lung cancer in the future.

We have more information on how to protect yourself from air pollution.

Existing lung conditions    

Conditions that cause inflammation in the airways, such as COPD, pneumonia, and tuberculosis, are linked with an increased risk of getting lung cancer.  

This is because sometimes inflammation can damage the lungs, increasing the chance of cells growing out of control and forming cancer.

Family history    

Your risk of lung cancer may be higher if your parents or siblings have had lung cancer.  

This is because cancer can be passed on through your genes. Your genes are the instructions that tell your body how to grow.

Lung cancer survival is improving over time. Survival is linked to the stage of disease. If the cancer is found and treated at an early stage, you will survive for longer.

Over half of people with stage 1 lung cancer will survive for more than five years after diagnosis.