Lung Cancer

What are the lungs?

There are two lungs, one on either side of the chest. Air goes in to the lungs via the windpipe (trachea) which divides into a series of branching airways called bronchi. Air goes from the airways into millions of tiny air sacs (alveoli).

Oxygen from the air is passed into the bloodstream through the thin walls of the alveoli.

What is cancer?

Cancer is a disease of the cells in the body. The body is made up from millions of tiny cells. There are many different types of cell in the body, and there are many different types of cancer which arise from different types of cell. What all types of cancer have in common is that the cancer cells are abnormal and multiply 'out of control'.

A malignant tumour is a 'lump' or 'growth' of tissue made up from cancer cells which continue to multiply. Malignant tumours invade into nearby tissues and organs which can cause damage. Malignant tumours may also spread to other parts of the body. This happens if some cells break off from the first (primary) tumour and are carried in the bloodstream or lymph channels to other parts of the body. These small groups of cells may then multiply to form 'secondary' tumours (metastases) in one or more parts of the body. These secondary tumours may then grow, invade and damage nearby tissues, and spread again.

Some cancers are more serious than others, some are more easily treated than others (particularly if diagnosed at an early stage), some have a better outlook (prognosis) than others.

So, cancer is not just one condition. In each case it is important to know exactly what type of cancer has developed, how large it has become, and whether it has spread. This will enable you to get reliable information on treatment options and outlook.

See separate leaflet called 'What are Cancer and Tumours' for further details about cancer in general.

What is lung cancer?

Primary lung cancers
Primary lung cancers arise from cells in the lung. There are several types of primary lung cancer. The two most common types are called squamous cell carcinoma and small cell carcinoma. Lung cancers called adenocarcinoma and large cell carcinoma are less common. All four of these types of lung cancer arise from various cells which line the airways (bronchi). There are some other rarer types of primary lung cancer which arise from other types of cells in the lung.

Each type of lung cancer has different properties. For example, small cell carcinoma grows and spreads (metastasises) rapidly. By the time small cell cancer is diagnosed, in most cases it has already spread to other parts of the body. In contrast, a squamous cell carcinoma tends to grow more slowly and may not spread to other parts of the body for some time.

Primary lung cancer is one of the most common cancers in the UK. There are about 80,000 new cases diagnosed each year in the UK.

Secondary lung cancers
Secondary lung cancers (or lung metastases) are tumours which have spread to the lung from another cancer somewhere else in the body. The lung is a common site for metastases from other cancers. This is because all blood flows through the lungs and may contain tumour cells from any other part of the body. Secondary lung cancers are not dealt with further in this leaflet.

Mesothelioma
This is a cancer of the pleura, a lining tissue which covers the lungs. Strictly speaking, mesothelioma is not a lung cancer and is dealt with in a separate leaflet.

What causes lung cancer?

A cancerous tumour starts from one abnormal cell. It is thought that something damages or alters certain genes in the cell. This makes the cell abnormal and multiply 'out of control'. Certain risk factors increase the chance of certain cancers forming. (See separate leaflet called 'What Causes Cancer' for more details.)

Smoking
Smoking is a major risk factor and is the main cause of lung cancer. Chemicals in tobacco smoke are carcinogens - substances which can damage cells. About 9 in 10 cases of lung cancer are caused by smoking. About 1 in 7 long-term smokers develop lung cancer. Lung cancer most commonly develops in people between the age of 45 and 70 who have smoked since they were young adults.

Other factors
Non smokers have a low risk of developing lung cancer. However, people who are regularly exposed to other peoples smoke (passive smokers) have a small increased risk. People who work with certain substances such as radioactive materials, asbestos, nickel and chromium have an increased risk, especially if they also smoke. People who live in areas where there is a high level of background radiation from radon have a small increased risk. Air pollution may be a small risk too.

What are the symptoms of lung cancer?

Initial symptoms of lung cancer include:

• Persistent cough.
• Coughing up blood, or bloodstained sputum.
• Mild chest pains.
• Shortness of breath or wheezing - especially if a tumour is growing in a main airway and is partially blocking the airflow.
• Clubbing. This is an odd shape of the fingernails. It is not clear why this develops but it is a 'marker' for lung cancer which doctors may notice when they examine you.
• Some lung cancers do not cause any symptoms until they are quite advanced.

As the cancer grows in the lung, the symptoms may become worse and may include:

• The same symptoms as above, but more severe.
• You may feel generally unwell, tired, or lose weight.
• Pneumonia (lung infection) may develop in a part of a lung 'blocked off' by a growing tumour.
• Fluid may accumulate between the lung and chest wall (pleural effusion). This can cause worsening shortness of breath.
• A tumour near to the top of the lung can press on nerves going down the arm and cause pain and weakness in the arm and shoulder, and other effects from 'trapped' nerves.
• Swelling of the face (face oedema) may develop if a tumour presses on a main vein coming towards the heart from the head.
• Some small cell tumours can produce large amounts of hormones which can cause symptoms in other parts of your body.

If the cancer spreads to other parts of the body, various other symptoms can develop.

How is lung cancer diagnosed?

If a doctor suspects that you may have lung cancer, the common initial test is a chest x-ray. This is a simple and quick test, and may show changes such as abnormal shadowing. However, a chest x-ray cannot confirm cancer as there are various causes of shadowing on a chest x-ray. Other tests are needed.

Confirming the diagnosis
For all suspected cancers, it is best to confirm the diagnosis by getting a small sample or 'biopsy'. The biopsy sample is then examined under the microscope to look for the abnormal cells of cancer. The type of cancer can also be determined from the sample (and other causes of the symptoms or abnormal tissue ruled out.) One or more of the following procedures may be done to obtain a sample for testing.

• Bronchoscopy is the most common procedure to look into the airways and to obtain a biopsy from a tumour in a main airway. A bronchoscope is a thin, flexible, telescope. It is about as thick as a pencil. The bronchoscope is passed through the nose, down the back of the throat, into the windpipe (trachea), and down into the bronchi. The fibre-optics allows light to shine round bends in the bronchoscope and so the doctor can see clearly inside your airways. A bronchoscope has a side channel down which a thin 'grabbing' instrument can pass. This can be used to take a small biopsy from tissue on the the inside lining of a bronchi. (See separate leaflet called 'Bronchoscopy' for more details.)
• Sputum culture. You may be asked to collect some sputum (phlegm). Cancer cells can sometimes be seen by looking at sputum with a microscope.
• Fine-needle biopsy. This is where a doctor inserts a thin needle through the chest wall to obtain a small sample of tissue. X-ray pictures of the suspected tumour help the guide the doctor to insert the needle into a suspected tumour. The skin is numbed with local anaesthetic to make the test as painless as possible.
• Pleural tap. If you have an accumulation of fluid next to the lung which may be due to a tumour, some fluid can be drained with a fine needle (similar to the above). The fluid is examined for cancer cells.
• Mediastinoscopy. This is used to inspect and biopsy lymph nodes in the centre of the chest (the mediastinum). It is usually done under a general anaesthetic. An instrument similar to a bronchoscope is used. A small cut is made in the neck and the instrument is pushed down next to the trachea.
• Thoracoscopy. Sometimes an instrument similar to a bronchoscope is inserted through a cut in the chest wall. This is done under general anaesthetic. It enables a doctor so see and biopsy lung tissue directly.

Assessing the extent and spread
If you are confirmed to have lung cancer, further tests may be done to assess if it has spread. For example, a CT scan, an MRI scan, a bone scan, a PET scan, or other tests. (There are separate leaflets which describe each of these tests in more detail.) This assessment is called 'staging' of the cancer. The aim of staging is to find out:

• How much the cancer in the lung has grown.
• Whether the cancer has spread to local lymph nodes or to other areas of the lungs.
• Whether the cancer has spread to other areas of the body (metastasised).

By finding out the stage of the cancer it helps doctors to advise on the best treatment options. It also gives a reasonable indication of outlook (prognosis). See separate leaflet called 'Cancer Staging' for details.

What are the treatment options for lung cancer?

Treatment options which may be considered include surgery, chemotherapy and radiotherapy. The treatment advised for each case depends on various factors such the site of the primary tumour in the lung, the type of the cancer, the stage of the cancer (how large the cancer is and whether it has spread), and your general health.

You should have a full discussion with a specialist who knows your case. They will be able to give the pros and cons, likely success rate, possible side-effects, and other details about the various possible treatment options for your type of cancer.

You should also discuss with your specialist the aims of treatment. For example:

• Treatment may aim to cure the cancer. Some lung cancers can be cured, particularly if they are treated in the early stages of the disease. (Doctors tend to use the word 'remission' rather than the word 'cured'. Remission means there is no evidence of cancer following treatment. If you are 'in remission', you may be cured. However, in some cases a cancer returns months or years later. This is why doctors are sometimes reluctant to use the word cured.)
• Treatment may aim to control the cancer. If a cure is not realistic, with treatment it is often possible limit the growth or spread of the cancer so that it progresses less rapidly. This may keep you free of symptoms for some time.
• Treatment may aim to ease symptoms. Even if a cure is not possible, treatments may be used to reduce the size of a cancer which may ease symptoms such as pain. If a cancer is advanced then you may require treatments such as nutritional supplements, painkillers, or other techniques to help keep you free of pain or other symptoms.

Surgery
An operation may be an option if the cancer is in an early stage. Surgery usually involves removing part or all of an affected lung. However, in many cases, the cancer has already spread when it is diagnosed and surgery is not usually then an option. Also, surgery may not be an option if your general health is poor. For example, if you have other lung problems such as chronic obstructive airways disease (COPD) which is also common in smokers.

Radiotherapy and chemotherapy
There are separate leaflets which give more details about these treatments. Briefly:

• Radiotherapy is a treatment which uses high energy beams of radiation which are focussed on cancerous tumours. This kills cancer cells, or stops cancer cells from multiplying.
• Chemotherapy is a treatment of cancer by using anti-cancer drugs which kill cancer cells, or stop them from multiplying.

What is the prognosis (outlook)?

The outlook is best in those who are diagnosed when the cancer is still small, and has not spread. Surgical removal of a tumour in an early stage may then give a good chance of cure. However, most people with lung cancer are diagnosed when the cancer has already spread. In this situation a cure is less likely. However, treatment can often slow down the progression of the cancer.

The treatment of cancer is a developing area of medicine. New treatments continue to be developed and the information on outlook above is very general. The specialist who knows your case can give more accurate information about your particular outlook, and how well your type and stage of cancer is likely to respond to treatment.

Further help and information

CancerBACUP, 3 Bath Place, Rivington Street, London, EC2A 3JR
Tel: 0808 800 1234    Web: www.cancerbacup.org.uk
Provides information and support to anyone affected by cancer.

Cancer Research UK
Their website www.cancerhelp.org.uk provides facts about cancer including treatment choices.

Other support groups
See Cancer Support Groups for a list of self help and support groups for cancer patients.

© EMIS and PIP 2004   Updated: May 2004   Review Date: June 2005   CHIQ Accredited