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 more questions, you can ask your doctor or nurse at the hospital where you are having your treatment.
How does cancer spread to the lung?
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 cancer or metastatic cancer.
Some cancers are more likely to spread to the lungs than others. These include:
- bowel (colon and rectum)
- 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 have tests to find where the cancer started. Occasionally, doctors may not be able to find the primary cancer. This is called cancer of unknown primary (CUP).
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 secondary lung cancer can include:
- a cough that does not get better
- feeling breathless
- coughing up blood (haemoptysis)
- pain or discomfort in the chest that does not go away
- a build-up of fluid in the pleura (pleural effusion).
Some people may have general symptoms, such as:
- weight loss
- loss of 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 do not feel better after treatment (such as antibiotics), your doctor should do more tests.
You may have different tests to diagnose secondary lung cancer, including one or more of the following tests.
Some people may need a biopsy. This means collecting samples of cells or tissue from the lung to check for cancer cells. Secondary lung cancer can make fluid collect in the space between the two membranes that surround the lungs (pleura). This is called a pleural effusion. If this happens, it may be possible for the doctor to remove some of the fluid and check it for cancer cells.
When the doctors look at the cancer cells, they can usually tell it is a secondary lung cancer. This is because the cells look like the cells from the primary cancer. For example, if a bowel cancer has spread to the lungs, the cells look like bowel cancer cells not lung cancer cells.
Waiting for test results can be a difficult time, we have more information that can help.
The treatment you have for secondary lung cancer depends on:
- the primary cancer
- your general health
- your 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 treat the symptoms. With certain cancers, the aim may be to try to cure the cancer.
Your cancer doctor and specialist nurse will talk to you about treatment options. You can ask them any questions you may have. You and your doctor can decide together on the best treatment plan for you.
The following treatments may be used for secondary lung cancer.
Chemotherapy is the use of anti-cancer (cytotoxic) drugs to destroy cancer cells. It is often given to shrink and control secondary cancers in the lung or to reduce symptoms. The chemotherapy drug you have depends on whether you have had chemotherapy before and how long ago. You usually have your treatment in a chemotherapy day unit.
If you have a cancer that relies on hormones to grow, such as breast cancer or prostate cancer, you may have hormonal therapy. The type of hormonal therapy you have depends on which hormonal treatments you have already had. There are several different types of hormonal therapy. They are usually given as tablets or injections.
Targeted therapy drugs interfere with the way cancer cells signal or interact with each other. This stops them growing and dividing. You may have a targeted therapy drug as an injection into a vein (intravenously) or as tablets.
Tumour ablation uses heat or cold to destroy cancer cells. Doctors sometimes use it instead of surgery for secondary lung cancer. Radiofrequency ablation (RFA) uses heat to destroy cancer cells. Cryoablation (cryotherapy) is when extreme cold is used to destroy cancer cells.
You may be offered some treatments as part of a clinical trial.
You may have other treatments to manage any symptoms caused by secondary lung cancer.
Breathlessness can be difficult to cope with, but there are treatments and drugs that can be used to help.
A blocked airway
Sometimes a secondary cancer in the lung can block one of the airways. This can make breathing difficult. The following treatments can help.
This uses heat to destroy cancer cells. This can help relieve the symptoms. You usually have this done under a general anaesthetic.
If the secondary cancer is causing pressure on the windpipe, a surgeon can insert a small tube (stent) to hold the windpipe open. You usually have this done under a general anaesthetic. You can breathe more easily with the stent in place. It does not generally cause any problems.
If the cancer is blocking one of the airways, you may have a type of internal radiotherapy (brachytherapy). Most people have only one session of treatment. It is usually done in an operating theatre. The doctor passes a thin tube (catheter) down the nose or throat into the lung, using a bronchoscope. They put a small piece of radioactive material inside the catheter, next to the cancer. They leave it in place for a few minutes to give a dose of radiation to the cancer. Then they remove it together with the catheter.
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. It may cause:
- a cough
- a dull, aching pain.
These symptoms can be relieved by carefully draining the fluid through a tube. We have more information about treating a pleural effusion.
A cough is a common symptom. There are different treatments that can help a cough, including:
- some types of painkiller that are given by mouth
- drugs given as a vapour that you inhale
- a short course of radiotherapy.
It is important to tell your doctor or nurse if you have any pain. There are different drugs that can be used to control pain. You can take painkillers in different ways, including:
- a liquid
- skin patches
- injections, usually under the skin.
Let your doctor or nurse know if your painkillers are not controlling the pain. They can increase the dose or give you a different drug. We have more information about managing pain.
Coughing up blood
You may notice some streaks of blood in your phlegm (sputum), but this does not usually cause a problem. If you notice larger amounts of blood, let your doctor know. You can have treatment to help control it, such as radiotherapy.
Finding out your cancer has spread or come back may be even more upsetting than hearing for the first time that you have cancer. You may have many different feelings, including:
These are all normal reactions.
Everyone has their own way of coping with difficult situations. Some people find it helpful to talk to family or friends. 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.
We have more information about coping with advanced cancer that you may find helpful.
Macmillan is also here to support you. If you would like to talk, you can: