What Is Lung Cancer? A Comprehensive Guide

Find out about the risk factors and symptoms of lung cancer and when to get tested

Lung cancer is one of the most common types of cancer, with more than 43,000 people in the UK being diagnosed every year.

This comprehensive guide takes a look at what lung cancer is, what causes it and the symptoms you need to look out for. It will also discuss when and how to be screened for lung cancer so that you can have the best chance of early diagnosis for the best possible survival rates.

What is lung cancer?

The lungs are two sponge-like organs that are housed in the chest and are the engine that drives your respiratory system.

When you breathe in, air enters your lungs through your nose or mouth and travels down your trachea (windpipe). The trachea splits into two tubes called bronchi, which go into the lungs and divide into smaller bronchi. These divide even further into bronchioles. At the end of each bronchiole are tiny air sacs called alveoli. These alveoli absorb oxygen into your blood when you inhale and remove carbon dioxide when you exhale.

Lung cancer typically starts in the trachea, bronchi, bronchioles, alveoli or lung tissue.

Types of lung cancer

There are two main types of lung cancer — non-small cell lung cancer and small cell lung cancer.

Other types of lung cancer include lung carcinoid tumours, adenoid cystic carcinomas, lymphomas, and sarcomas, as well as cancers that have started in other areas of the body and have spread (metastasized) to the lungs.

Non-small cell lung cancer is the most common type of lung cancer with approximately 88% of all lung cancer patients having this type.

Small-cell lung cancer is fast-growing and the most aggressive type of lung cancer. It is a less common form, accounting for approximately 12% of all lung cancers and, in the majority of cases, is caused by smoking. Small-cell lung cancer occurs more frequently in men than women.

Adenocarcinoma is a non-small cell lung cancer that is more commonly found in women and non-smokers, and it’s the most common type of lung cancer for people under 45. The incidence of adenocarcinoma of the lung is on the increase in the UK and it is now one of the most common types of lung cancer.

Adenocarcinoma accounts for approximately 50% of all non-small cell lung cancers and begins in the outer sections of the lung (although it can occur as central lesions) which can make it difficult to detect in the early stages of the disease. It develops from lung cells that produce mucus and, unlike many other types of lung cancer, it is more likely to remain in one area, giving better opportunities for treatment.

Lung cancer symptoms

In most cases, people with early stages of lung cancer will have no signs or symptoms.

Symptoms may develop as the disease progresses over time. Any symptoms that are present will vary depending on how advanced the cancer is and its position.

The main symptoms of lung cancer to look out for include:

  • Loss of appetite
  • Unexplained fatigue and weakness
  • Unintentional weight loss
  • A persistent cough or a change in a long-standing cough
  • Persistent breathlessness or shortness of breath
  • Headaches
  • Coughing up blood (phlegm with blood in it)
  • Aches or pains when breathing or coughing
  • Persistent chest infections that don’t respond to medical treatment

The following symptoms are less common and are usually associated with the more advanced stages of lung cancer:

  • Difficulty swallowing (dysphagia)
  • A hoarse voice
  • Finger clubbing – changes to the shape of the fingers and fingernails
  • Swelling of the face and neck, which may be due to obstruction of the venous drainage
  • Persistent pain in the chest and/or shoulder
  • Pain and swelling in the joints
  • Bone pain

Many of these signs and symptoms can also be caused by other medical conditions, so are not always indicators of cancer. Nevertheless, if you have any of these symptoms, it’s important to always see a doctor. Lung cancer is much easier to treat when detected early.

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Lung cancer causes and risk factors

Anything that can increase your chance of getting a disease, such as lung cancer, is called a risk factor.

Smoking tobacco is the largest risk factor in developing lung cancer and is the biggest cause of lung cancer in the UK — around 72% of lung cancer deaths in the UK are caused by smoking. Overall, smoking is estimated to be responsible for more than 21% of all cancer deaths in the UK.

Even occasional or light smoking increases the risk of lung cancer, and your risk goes up the longer and more you smoke. Exposure to second-hand smoke, even if you don't smoke yourself, can also increase your risk of lung cancer.

In addition to smoking, key risks factors that can increase your chance of developing lung cancer include:

Family History

A family history of lung cancer in a first-degree relative (parent/sibling/child) is associated with a two-fold increased risk, independent of smoking. Lung cancer is more common in White than in Black or Asian people.

Exposure to radon gas

Radon gas is a naturally occurring radioactive gas that comes from the breakdown of tiny amounts of uranium in rock, soil and water. As radon gas is produced, it goes into the air and enters your lungs as you breathe, increasing your risk of developing lung cancer.

Unsafe levels of radon gas can build up in homes and other buildings, and certain areas of the UK, such as the southwest of England, have been identified as having higher-than-average levels.

Exposure to certain chemicals

Exposure to carcinogenic (cancer-causing) chemicals and materials such as asbestos, silica and diesel engine exhaust fumes can increase the risk of lung cancer. People who are often exposed to high levels of these substances include workers in industries such as construction, glassmaking, bricklaying, mechanics and transportation.

Air pollution

Outdoor air pollution is responsible for causing around 1 out of 10 lung cancer cases in the UK. Your personal risk depends on the levels of air pollution you’re regularly exposed to.

Previous radiation therapy

Your risk of developing lung cancer may be increased if you've had radiotherapy to your chest for another type of cancer in the past.

Previous lung disease

Having lung diseases including chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF) in the past can increase your risk of developing lung cancer compared to those who have not had a previous lung condition.

How is lung cancer diagnosed?

If you’re experiencing any of the symptoms listed above, are over 50 years old or are worried about your health, it’s important to see a doctor to seek a diagnosis.

Identifying lung cancer in its earliest stages means that treatment is much more effective, leading to a much higher survival rate. More than 55 out of 100 people with stage 1 lung cancer will survive their cancer for five years or more after diagnosis. This drops to only 5 in 100 people when diagnosed in the latest stage (stage 4).

Tests for lung cancer

When you see your doctor, they’ll run some diagnostic tests based on your symptoms and personal risk factors. They’ll likely measure your blood pressure, heart rate and temperature and may also record your height and weight.

You may be asked to breathe into a small device called a spirometer, which measures the amount of air you breathe in and out and how quickly you breathe.

If your doctor suspects you could have lung cancer, they will likely arrange for you to have blood tests. Depending on your symptoms and test results, they may also refer you to a specialist for further tests such as a chest x-ray, CT scan, PET-CT scan, MRI, bronchoscopy and biopsy, and other types of biopsies.

There's currently no national screening programme for lung cancer in the UK, but at-home testing can help you identify the early signs of the disease. Regular screening is especially important if you’re over 50, have been or are a smoker, or are at an increased risk of developing lung cancer.

Thanks to advances in technology, you can now screen for lung cancer from the comfort of your own home. Check4Cancer offers a unique, easy-to-use at-home lung cancer test, LungCheck, that screens for antibodies that can be linked to an increased risk of developing lung cancer, for earlier detection and better outcomes.

Lung cancer stages

The stage of cancer indicates how big it is and if it has spread to other areas of the body. Identifying which stage you have helps your doctor devise the most suitable and effective treatment plan for you. The stage also gives some idea of your prognosis.

  • Stage 1 – In the first stage, lung cancer is usually small and is contained in the lungs (hasn’t spread to other areas of the body).
  • Stage 2 – In stage 2 lung cancer, a tumour is usually larger than in stage 1. In most cases, the cancer hasn’t spread to the surrounding tissue, but stage 2 can mean that cancer cells have spread into lymph nodes close to the tumour.
  • Stage 3 – At stage 3, the cancer is larger, there are cancer cells in the lymph nodes nearby and it may have started to spread into surrounding tissues.
  • Stage 4 – If you have stage 4 lung cancer, this means that your cancer has spread from your lungs into other areas of your body. This stage is also called secondary lung cancer or metastatic lung cancer.

The stage of your cancer will be determined during testing, most often through scans including CT, MRI, PET and bone scans.

Lung cancer treatment

The treatment you’ll need depends on the type and stage of lung cancer you have as well as your general health. Before you start treatment, a specialist team will meet to discuss the best treatment plan for you.

Treatments for lung cancer may include surgery, radiotherapy, chemotherapy, targeted drug therapy, immunotherapy or a combination of these.

Before you start treatment, your doctor will take you through what each option entails and explain any side effects. Together, you’ll also discuss anything you should consider when making treatment decisions.

How to reduce your risk of lung cancer

There are several lifestyle changes you can make to significantly reduce your risk of lung cancer. These include:

  • Not starting smoking – if you’ve never smoked, don’t start now. And avoid second-hand smoke whenever possible
  • Stopping smoking – find out more about starting a smoking cessation programme with the NHS
  • Avoid carcinogens – take precautions such as wearing a mask to protect yourself from exposure to harmful chemicals
  • Maintain a healthy lifestyle – eat a well-balanced diet full of fruit and vegetables and aim to do at least 150 minutes of moderate-intensity exercise a week
  • If you are a smoker or if a close family member has had lung cancer, consider lung cancer screening from age 50+

The best way to reduce your risk of lung cancer is to stop smoking as soon as possible if you smoke. Stopping smoking has an immediate positive impact on your lung health — halting further damage and beginning your lungs’ healing process. Read our article Lung Recovery After Smoking: Can Lungs Repair Themselves? for an in-depth look at the benefits of quitting smoking and how your lungs can repair themselves after your last cigarette.

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Why should I get tested for lung cancer?

As with all cancers, survival rates for lung cancer depend on the stage at which the disease is detected, as well as other general factors such as your general health and sex.

Regular screening is key to the early detection of lung cancer, which is vital to successful treatment and increased survival rates.

How can I get tested for lung cancer?

Check4Cancer’s at-home LungCheck test is a quick and easy way to detect lung cancer in its early stages and will also assess your risk of developing the disease.

If you are worried about non-small cell lung cancer or any other type of lung cancer and think you may have symptoms or be at risk, please contact Check4Cancer to arrange a LungCheck.

Check4Cancer’s LungCheck will report on your blood sample, which tests for seven antibodies to lung cancer and provide you with a personalised screening programme.

Order a LungCheck test kit

Order your LungCheck test kit today, and receive your results within 14 days.

An abnormal result does not necessarily mean you have lung cancer. If you receive an abnormal test result, and meet the clinical criteria, we’ll refer you for a CT scan.

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Order your LungCheck test today

Order your LungCheck test today

LungCheck is a unique easy to use at-home test kit that screens for lung cancer. There are more than 47,000 lung cancers diagnosed each year in the UK. The chances of survival from lung cancer are extremely good if detected early but unfortunately many people present at a later stage by the time symptoms develop.