Tens of thousands of people are diagnosed with lung cancer every year in the UK.
The NHS describes it as one of the most common and serious forms of the disease.
Around 47,000 people are diagnosed annually across Great Britain and Northern Ireland.
It mainly affects older people, with more than four in 10 of those diagnosed in the UK aged 75 and above, the NHS website states, adding that the condition is rare in people under 40.
While smoking is the most common cause, people who have never smoked can also develop lung cancer.
The British Lung Foundation (BLF) said around 85% of cases occur in people who smoke or who used to smoke.
For people who stop smoking, the risk decreases over time, according to the charity, which says that after 10 years the risk of lung cancer falls to half that of a smoker.
The BLF said it is increasingly recognised that other factors including air pollution are associated with an increased risk of getting the disease.
It said people who have never smoked are more likely to develop a particular type of lung cancer called adenocarcinoma.
There are usually no signs or symptoms in the early stages of lung cancer, with noticeable symptoms often not becoming apparent until it has spread through the lungs or into other parts of the body.
The NHS advises that people with a persistent cough, coughing up blood, persistent breathlessness, unexplained tiredness and weight loss, oran ache or pain when breathing or coughing should see a GP.
Around a third of people with lung cancer live for at least one year after their diagnosis and about one in 20 people live for least 10 years, the NHS said, adding that survival rates vary widely and that early diagnosis can make a big difference.
The main treatments for lung cancer are surgery, drug therapies, radiotherapy and palliative care, the BLF said.
:: Macmillan Cancer Support said anyone with questions or concerns about cancer can call 0808 808 00 00 to speak to a specially trained nurse on the free support line, which is open every day from 8am-8pm.