Secondary cancer in the lung is when cancer cells have spread to the lungs from a cancer that started somewhere else in the body.

We have separate information about cancer that starts in the lung (primary lung cancer).

We hope this information answers your questions. If you have any further questions, you can ask your doctor or nurse at the hospital where you are having your treatment.

The lungs are the parts of our body that we use to breathe. We have two lungs (right and left). The lungs are divided into areas called lobes. The right lung has three lobes and the left lung has two.

When we breathe in, air passes from our nose or mouth through to the windpipe (trachea). The trachea divides into two tubes (right and left bronchus) that go to each lung. These divide into smaller tubes called bronchioles. At the end of the bronchioles, there are tiny air sacs called alveoli. This is where oxygen from the air we’ve breathed in (inhaled) passes into the blood and is circulated around the body. A waste gas called carbon dioxide passes from the blood into the air sacs (alveoli). We get rid of carbon dioxide when we breathe out (exhale).

The lungs are covered by a lining called the pleura, which has two layers. The inner layer covers the lungs. The outer layer lines the ribcage and a sheet of muscle called the diaphragm.

Sometimes cancer cells break away from the part of the body where the cancer started (primary cancer). They can travel in the blood or the lymphatic system to another part of the body, such as the lungs. This is called secondary lung cancer or metastatic cancer.

Some cancers are more likely to spread to the lungs than others. These include:

• bowel (colon and rectum)
• breast
• bladder
• testicle
• stomach
• gullet (oesophagus)
• kidney (renal)
• melanoma (a type of skin cancer)
• sarcomas (bone and soft tissue sarcomas).

Sometimes, people are diagnosed with a secondary cancer before the primary cancer has been diagnosed. In this case, you’ll have tests to find where the cancer started. Occasionally, doctors may not be able to find the primary cancer. This is called an unknown primary.

Some people may not have any symptoms. Secondary lung cancer may be diagnosed after a routine scan or during a chest x-ray for another condition.

Symptoms of a secondary lung cancer can include:

• a cough that doesn't clear up
• feeling breathless
• coughing up blood in your phlegm (sputum)
• pain or discomfort in your chest that doesn’t go away
• a build up of fluid in the pleura (pleural effusion).

Some people may have general symptoms such as tiredness, weight loss or losing their appetite.

These symptoms can be caused by conditions other than cancer, for example a chest infection. Always see your doctor if you have any of these symptoms. If you don’t feel better after treatment such as antibiotics, your doctor should do some further tests.

You may have different tests to diagnose a secondary lung cancer, including:

Chest x-ray

This may be the first test you have.

CT (computerised tomography) scan

A CT scan takes a series of x-rays that build up a three-dimensional picture of the inside of the body. The scan is painless and takes 10–15 minutes. CT scans use a small amount of radiation, which is unlikely to harm you or anyone you come into contact with. You may be asked to not eat or drink for at least four hours before the scan.

You may be given a drink or injection of a dye, which allows particular areas to be seen more clearly. This can make you feel hot all over for a few minutes. It’s important to let your doctor know if you’re allergic to iodine or have asthma, because you could have a more serious reaction to the injection.

PET (positron emission tomography) scan

This uses low-dose radioactive sugar to measure the activity of cells in different parts of the body. A very small amount of a mildly radioactive substance is injected into a vein, usually in your arm. You have a scan a couple of hours later. Areas of cancer are usually more active than surrounding tissue and show up on the scan. 

Biopsy

Some people may need a biopsy. You usually have this done in the x-ray department, during a CT scan. The biopsy may be done by a doctor who specialises in lung surgery (thoracic surgeon). The doctor will inject some local anaesthetic into the area to numb it. They gently insert a needle through your skin and into the lung to remove a small sample of cells to be examined under a microscope. The biopsy may be slightly uncomfortable but only takes a few minutes. 

Secondary lung cancer may cause fluid to collect in the space between the two membranes that surround the lungs. This is called a pleural effusion. If this happens, it may be possible to remove some of the fluid and examine it for cancer cells.

When the cancer cells are examined, doctors can usually tell it’s a secondary lung cancer because the cells look like the cells from the primary cancer. For example, if a bowel cancer has spread to the lungs, the cells will look like bowel cancer cells not lung cancer cells.

The treatment you have for secondary lung cancer depends on the primary cancer, your general health and your own preferences. Treatment is usually with drugs or treatments that are used for the primary cancer.

Usually the aim of treatment is to control the cancer and to treat the symptoms. With certain cancers, the aim may still be to try to cure the cancer.

Your cancer doctor and specialist nurse will talk to you about possible options for treatment. You can ask them any questions you may have. You and your doctor can decide together on the best treatment plan for you.

Chemotherapy

Chemotherapy is often given to shrink and control secondary cancers in the lung. It also helps to reduce symptoms. Chemotherapy can be given into a vein (intravenous) or as tablets. The drug you have will depend on whether you've had chemotherapy before and how long ago. You usually have your treatment in a chemotherapy day unit. We have more information about chemotherapy.

Hormonal therapy

If you have a cancer that relies on hormones to grow – such as breast or prostate cancer – you may be given hormonal therapy. The type of hormonal therapy you have will depend on which hormonal treatments you've already been given.

Targeted therapy

These are drugs which target specific proteins on the cancer cells to stop them from growing. You may have a targeted therapy as an injection into a vein (intravenous) or as tablets.

Radiotherapy

You might have a short course of radiotherapy to relieve symptoms of secondary lung cancer, such as breathlessness or coughing up blood (haemoptysis).

Surgery

Surgery to remove the secondary lung cancer may occasionally be possible. It is usually only done if the secondary cancer is small and in one area of the lung and if it has not spread anywhere else in the body.

Ablation

Ablation is when heat or cold is used to destroy cancer cells. It is sometimes used instead of surgery.

Radiofrequency ablation (RFA) uses heat to destroy cancer cells. RFA is usually done under general anaesthetic, but sometimes you can have it using a local anaesthetic. The doctor uses an ultrasound or a CT scan to guide the procedure. A probe called an electrode applies electrical current (radiofrequency) to a tumour. The current heats the cancer cells to a high temperature which destroys (ablates) them.

Sometimes ablation is done using a probe that produces microwaves (heat) to destroy the cancer cells. Cryoablation is when extreme cold is used to destroy cancer cells.

There are different ways in which your symptoms can be managed or treated.

Breathlessness

Breathlessness can be difficult to cope with but there are treatments and drugs that can be used to help.

There are also things that you can do yourself. These include using a technique called controlled breathing. This uses your diaphragm and lower chest muscles to help you breathe more gently and effectively.

Learning simple relaxation techniques that you can do at home may also help you to relax and breathe more easily. You may want to try the following:

• Make sure you sit down when you’re getting dressed and wear loose-fitting clothes.
• Having a chair in a hallway or on a landing means you can take a rest when walking between rooms.
• Using a hand held fan or sitting by an open window with cool air blowing on to your face can help you feel less breathless.

We have more information about managing breathlessness. We can also send you a copy of our CD, Relax and Breathe.

Treating a blocked airway

Sometimes a secondary cancer in the lungs can block one of the airways. This can make breathing difficult. There are a number of treatments that can help.

Laser treatment

This uses heat to destroy cancer cells which can help to relieve the symptoms. You usually have this done under a general anaesthetic.

Stents

If the secondary cancer is causing pressure on the windpipe, a small tube called a stent may be inserted to hold the windpipe open. You usually have this done under a general anaesthetic. You’ll be able to breathe more easily with the stent in place. It does not generally cause any problems.

Internal radiotherapy

You may have a type of internal radiotherapy (brachytherapy) called endobronchial radiotherapy. The doctor uses a flexible tube called a bronchoscope to place a thin tube (catheter) containing radioactive material close to the tumour. The radioactive material is left in place for a few minutes to give a dose of radiation to the tumour. It is then removed together with the catheter. You usually only need one treatment.

Fluid on the lung (pleural effusion)

A secondary lung cancer can cause a build-up of fluid between the two membranes (pleura) that cover the lungs. This is called a pleural effusion. The fluid puts pressure on the lung and may cause breathlessness, a cough and a dull, aching pain. These symptoms can be relieved by carefully draining the fluid through a tube.

Your doctor will make a small cut in your chest and insert a tube into the space where the fluid is collecting. They will draw the fluid into a syringe, or attach the tube to a bag or bottle for the fluid to drain into.

Sometimes it’s possible to try to seal the two layers of the pleura back together to prevent the fluid from building up again. Doctors use talc mixed with saline (sterile salt water) and insert it into the space between the two layers which helps them stick together. This is called pleurodesis.

Cough

A cough is a common symptom. There are different treatments that can help a cough. Some types of painkilling drugs given by mouth can help. You can have other drugs as a vapour that you inhale. A short course of radiotherapy can also help to improve a cough.

Pain

It’s important to tell your doctor or nurse if you have any pain. There are different drugs that can be used to control pain. You usually take painkillers by mouth, as tablets or capsules, or as a liquid. You can also have them in other ways, such as skin patches or as injections, usually under the skin.

Let your doctor or nurse know if your pain killers are not controlling the pain. They can increase the dose or change you to a different drug.

We have more information on controlling cancer pain.

Coughing up blood

You may notice some streaks of blood in your phlegm (sputum) but this doesn’t usually cause a problem. If you notice larger amounts of blood, let your doctor know. You can have treatment, such as radiotherapy to help control it.

Research into new ways of treating cancer is ongoing. Doctors are always looking for improved ways of treating cancer and they do this by using clinical trials. Many hospitals now take part in these trials. Before any trial is allowed to take place it must have been approved by an ethics committee, which checks that the trial is in the interest of patients.

You may be asked to take part in a clinical trial. Your doctor will discuss the treatment with you so you have a full understanding of the trial. You may decide not to take part, or withdraw from a trial, at any stage. You'll then receive the best standard treatment.

Learning that your cancer has spread or come back may be even more devastating than hearing for the first time that you have cancer. You may have many different emotions, including anger, resentment, guilt, anxiety and fear. These are all normal reactions, and are part of the process many people go through in trying to come to terms with their illness.

Everyone has their own way of coping with difficult situations; some people find it helpful to talk to family or friends, while others prefer to seek help from people outside their situation. Some people prefer to keep their feelings to themselves. There is no right or wrong way to cope, but help is available if you need it.

Our cancer support specialists can give you details of counselling services in your area.