What is Lung Cancer?

Worldwide, cancer is a leading cause of death. The World Health Organization found that cancer accounted for nearly 10 million deaths in 2020. In the UK lung cancer has high mortality rates. Cancer Research UK found that between 2016 and 2018 there were 48,549 new lung cancer diagnoses.

Sadly, 34,771 people died of lung cancer between 2017 and 2019. It is the most common cause of cancer death in the UK with approximately 95 deaths relating to lung cancer every day.

However, as research has progressed, 10% of people can survive lung cancer and live free from the disease for 10 years or more. It is a preventable disease where following healthy lifestyle advice can reduce your chances of developing the disease.

Lung cancer is an extremely common form of cancer, with it being the third most common cancer in men and the second most common cancer in women alone. There has been an increase in women developing the disease, whereas in men there has been a decrease in diagnoses. It has a higher incidence rate in older people, particularly those aged 85 to 89 years.

What is lung cancer?

Lung cancer is a type of cancer that starts in the lungs. The lungs are the respiratory organs that take oxygen in when you inhale and release carbon dioxide when you exhale. Other types of cancers can spread to the lungs and cause secondary lung cancer (which is also known as lung metastases). But the cancer must start in the lungs for it to be a primary lung cancer.

There are two main types of lung cancer, which are:

• Non-small cell lung cancer.
• Small cell lung cancer.

There is also a type of cancer that affects the lining that covers the lung which is called pleural mesothelioma. The pleura is the membrane of the lung (a thin lining that covers the outer surface of the lung).

We will now explain the two main types of lung cancer.

Non-small cell lung cancer

This is the most common form of lung cancer and has three main types:

1. Adenocarcinoma – This develops from the cell that makes mucus.

2. Squamous – This develops from the cell that lines the airways.

3. Large cell – This is a very uncommon form of lung cancer that starts in the middle of the lungs.

Small cell lung cancer

This is a less common form of lung cancer with approximately 1 in 7 people with lung cancer having small cell lung cancer. As the name suggests, it develops from smaller cells in the body.

What are the signs and symptoms of lung cancer?

Lung cancer can go undetected for a while because, at first, it often does not present with any symptoms.

The main symptoms of lung cancer include:

• A persistent cough lasting for more than three weeks.
• A cough you have that changes but is an ongoing issue.
• Repeatedly getting a chest infection.
• Chest infections that are difficult to treat.
• Breathlessness.
• Wheezing during inhaling.
• Coughing up blood.
• Chest pain.
• Shoulder pain.
• Voice turning more husky or horsey.
• Loss of appetite.
• Losing weight whilst not trying to.
• Extreme tiredness.

Alone these symptoms may not appear concerning but it is important that you visit a doctor if you notice any of these symptoms or notice a mixture of symptoms. This is because the earlier the cancer is diagnosed the greater the chance of treatment being successful.

The symptoms described above are the most common symptoms that are associated with lung cancer, but there are some other symptoms that can be associated with the disease.

We have listed the less common symptoms below:

• Fingertips becoming larger.
• Fingertips becoming curved.
• Shoulder pain that travels down the arm.

What causes lung cancer?

The largest cause of lung cancer is smoking tobacco. This can be in the form of cigarettes, rolling tobacco, cigars, pipes, snuff (a powdered form of tobacco), and chewing tobacco. Tobacco contains nicotine, which is the addictive substance that leads people to smoke. However, it is the harmful chemicals that are also in smoking products that poison the body and create the risk of cancer.

Even people who do not smoke and have never smoked in their life can still develop the disease. This can be linked to second-hand smoke (where a non-smoker has inhaled the smoke of a smoker), but this is not always the case.

One positive factor about the lungs is that they can repair themselves over time from the damage of smoking. This means that when a person quits smoking for a long period of time, they can significantly reduce the chance of developing lung cancer. Doctors can provide advice, support and tools to help people to stop smoking. This includes counselling sessions, medications and nicotine replacement products.

As well as these, there are many online resources to support people with an addiction to smoking such as NHS Better Health. Smoking does not only cause lung cancer, but it can be a leading cause of other types of cancer too, including oral cancer.

Another cause of lung cancer is exposure to radon. Radon is a natural radioactive gas that is released from uranium. Uranium is present in rocks and soil and can sometimes be found in buildings. When radon is breathed in, it can cause damage to the lungs. This can be exacerbated further if the person exposed is also a smoker. Radon exposure is responsible for a small number of deaths in the UK.

There are other chemicals and substances that can cause lung cancer when inhaled. A lot of these chemicals can be found in many manual labour and industrial related work such as construction. The Health and Safety Executive include the risk elements in their guidance.

These chemicals and substances include:

• Arsenic – This is a poison that can be naturally found in the groundwater of many countries. People can become exposed to this through ingesting contaminated water or food.
• Asbestos – This is a naturally occurring carcinogen and mineral that can be found in old buildings. This is because this naturally occurring fibre was used in the construction industry before the 1990s. However, inhalation of these fibres is a serious health hazard.
• Beryllium – This is a common metal element used in the aviation industry. It can be harmful when breathed in.
• Cadmium – Breathing in high levels of this element can cause damage to the lungs. It is mainly a risk of exposure during manufacturing.
• Coal fumes – Burning coal releases several harmful chemicals. When these are inhaled it can increase the risk of cancer developing.
• Silica – This is naturally found in most rocks, sand and clay. It is found in construction materials where prolonged exposure is a great risk of causing lung cancer and other respiratory diseases.
• Nickel – Exposure to the compounds of nickel can increase the risk of lung cancer when workers breathe dust containing high levels of nickel compounds.
• Diesel fumes – Diesel engine exhaust fumes have been linked to being carcinogenic to humans with an increased risk of lung cancer.

What are the risk factors of lung cancer?

Statistics show that 8% of males will develop lung cancer over their lifetime and 7% of females will develop lung cancer over their lifetime. All causes listed above are risk factors for lung cancer developing. However, as well as this there are other characteristics that can increase the likelihood of lung cancer developing.

The largest contributing risk factor is age, as lung cancer is most likely in older adults. This is due to DNA damage over the years. This can be a result of biological processes and exposure to other risk factors.

Another high-risk factor for lung cancer is air pollution. In the previous section we listed many elements and chemicals that can cause cancer when inhaled for extended periods.

Many of these elements came from industrial sectors such as industrial manufacturing and construction. Due to this, if you live near major roads or have a job where exposure is frequent this can increase your risk of lung cancer in older age.

A family history of lung cancer can also make developing the disease more likely. This is mostly for people who have siblings or parents who have had lung cancer. As well as this, conditions such as pneumonia and Chronic Obstructive Pulmonary Disease (COPD) can be associated with lung cancer, but do not cause the illness.

Can lung cancer be prevented?

The best way to prevent lung cancer is by stopping smoking. This can also prevent other illnesses from developing. The NHS reports that after 12 years of not smoking, the risk of developing lung cancer can be half, and after 15 years of not smoking the chances of developing lung cancer reduce to the same as someone who has never smoked.

Keeping a healthy lifestyle can reduce the risk of lung cancer. A balanced diet is one that is low in fat, high in fibre, and meets five portions of fruit and vegetables per day. Regular exercise also contributes to a healthy lifestyle.

This includes two and a half hours of moderate intensity activity every week and some strength training to maintain muscle strength. Regular exercise can particularly lower the risk of getting lung cancer in people who previously smoked tobacco.

What are the stages of lung cancer?

You may have heard of different stages of lung cancer. The stages describe the size and position of the cancer and how far it has spread around the body (if at all). The stages then link to the type of treatment that will be best.

The stages range from stage 1 to stage 4, described below, which all relate to non-small cell lung cancer:

Stage 1

Stage 1 lung cancer refers to lung cancer that is no bigger than 4cm and has not spread to the lymph nodes or anywhere outside the lung. This is the earliest form of lung cancer.

Stage 2

Stage 2 lung cancer means that the cancer has spread to the lymph nodes or other parts of the lung, including areas just outside the lung. The cancer can be any size rather than a maximum of 4cm. This is referred to locally advanced lung cancer.

Stage 3

Stage 3 lung cancer has spread to the lymph nodes and is growing into other parts of the lung, the airways, and surrounding areas outside the lung. It may also have spread to tissues and structures further away from the lung, but not to other parts of the body. This stage of lung cancer is also referred to as locally advanced lung cancer.

Stage 4

Stage 4 lung cancer means that it has spread further away from the lungs. It may have spread to the lymph nodes plus the other lung, the pleura, the heart, and other parts of the body (including the liver, brain and bones). Stage 4 cancer is also referred to as metastatic lung cancer.

There are two stages of small cell lung cancer which are detailed below:

Limited stage

This is where the cancer cells are only in one lung and nearby lymph nodes.

Extensive stage

This is where the cancer has spread outside of the lung to the chest area and other parts of the body. This can happen quite early in the cancer due to the cancer cells spreading through the blood or lymphatic system.

The cells are extremely small in this type of lung cancer so a spread of the cancerous cells cannot always be identified in scan results. Due to this, most treatment of this stage of lung cancer is treated as if the cells have spread.

Can lung cancer be detected early?

Lung cancer is often detected early when a person is having tests for a different condition because, sometimes, symptoms of the disease can take a while to become apparent. This means that people do not visit the doctor for any tests because they do not feel a symptom for anything straight away. If you or a loved one notice unusual symptoms that can be linked to lung cancer, you should contact your GP straight away.

How is lung cancer diagnosed?

A chest x-ray is usually the first port of call for lung cancer diagnosis. This is because most lung cancers show up on x-ray results as a white or grey mass. If a mass is detected, further scans are required to rule out other conditions which could cause a mass, such as a lung abscess.

The scans completed after an initial chest x-ray include:

• CT scan – This uses x-rays and a computer to produce a higher detailed image of the internal body. It requires patients to have a dye injection which helps improve the quality of images.
• PET-CT scan – If a CT scan suggests cancer, a PET-CT scan can show where the active cancer cells are in the body and help to determine what treatment may be necessary.
• Biopsy – A biopsy uses a needle to obtain a sample of cells for testing. Some examples of biopsy include a mediastinoscopy.
• Bronchoscopy – This form of scan focuses on the airways and obtains a small sample of cells for further testing.

How is lung cancer treated?

The type of lung cancer treatment offered depends on the type of lung cancer you have (such as small cell or non-small cell). It also depends on the size, position and stage of the cancer, as well as your state of overall health.

This is because cancer treatment can be aggressive so the person must be strong enough to manage the effects of the treatment as this can take its toll on the body, creating other health issues.

The most common forms of treatment for lung cancer are chemotherapy and radiotherapy, which will be explained in more detail below:

Chemotherapy

This treatment is used when the cancer has spread or is at risk of spreading. It works by killing the cancerous cells in the body and can be used alone or in conjunction with radiotherapy. The chemotherapy is administered intravenously or orally in tablet form.

Chemotherapy requires several treatments that are spread out over the course of a few months. The number of treatments depends on the person and their type of lung cancer. However, it is not without its side effects. Due to the strength of the drug, it can kill healthy cells in the body as well as the cancerous cells.

 It can cause unpleasant side effects which include:

• Extreme tiredness.
• Hair loss.
• Sickness.
• Sore mouth.
• Itchy and dry skin.
• Lowers immune system.
• Diarrhoea.
• Constipation.

The side effects can reduce and will stop once treatment is complete.

Radiotherapy

Radiotherapy is used in early lung cancer stages or in conjunction with chemotherapy to stop the spread of the cells.

Radiotherapy can be given externally by a machine, through implants (where small radioactive pieces of metal are placed inside the body near the cancer), intravenously, or orally. This treatment is usually spread over several weeks and patients can usually go home after each treatment session.

However, like chemotherapy, radiotherapy has its side effects including:

• Sore skin that may change to lighter or darker.
• Hair loss.
• Sickness.
• Loss of appetite.
• Sore mouth.
• Diarrhoea.
• Tiredness.

The side effects can reduce and will stop once treatment is complete.

Unfortunately, there is no single cure for cancer, but as research progresses so do the treatment outcomes. Whether a person’s cancer can be successfully treated depends on many factors relating to that specific person and the type of lung cancer they have. Once treatment is complete, professionals may advise that you are in remission, instead of using the term ‘cured’.

This means that the cancer has responded to the treatment and is under control. However, there is a chance that the cancer can come back, and the period of remission can last for many years. The best chance of improving outcomes for cancer is in prevention. Maintaining a smoke-free and healthy lifestyle offers the best chance of a cancer-free life.