What is secondary lung cancer?

Secondary cancer in the lung is when cancer cells 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:

Some people are diagnosed with a secondary cancer before the primary cancer has been diagnosed. If this happens, 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).

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Symptoms of secondary lung cancer

Some people with secondary lung cancer may not have any lung cancer 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.

Some people may have general symptoms such as:

  • tiredness
  • 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 can do more tests.

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Diagnosis of secondary lung cancer

You may have one or more of the following tests to diagnose secondary lung cancer:

  • Chest x-ray

    A chest x-ray may be the first test you have. It is to check your lungs for anything that looks abnormal.

  • CT scan

    A CT scan takes a series of x-rays that build up a 3D picture of the inside of the body.

  • PET scan

    A PET scan uses low-dose radiation to measure the activity of cells in different parts of the body.

  • Biopsy

    You may need to have a biopsy. This is when samples of cells or tissue are collected from the lung so that doctors can check for cancer cells. 

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

Waiting for test results can be a difficult time. We have more information that can help.

Treatment for secondary lung cancer

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 cure the cancer.

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

  • Chemotherapy

    Chemotherapy is the use of anti-cancer (cytotoxic) drugs to destroy cancer cells. You usually have it to shrink and control secondary cancers in the lung and to reduce symptoms. The chemotherapy drug you have depends on where doctors think the cancer started (the primary cancer), whether you have had chemotherapy before, and how long ago.

  • Hormonal therapy

    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 whether you have already had hormonal treatments. There are several different types of hormonal therapy. You usually have it as tablets or injections.

  • Targeted therapy

    Targeted therapy drugs interfere with the way cancer cells 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.

  • Immunotherapy drugs

    Immunotherapy drugs help stimulate your immune system to recognise and destroy cancer cells. Depending on the type of tumour you have, you might have an immunotherapy drug.

  • Radiotherapy

    Radiotherapy treats cancer by using high-energy x-rays. You might have a short course of radiotherapy to relieve symptoms of secondary lung cancer, such as breathlessness or coughing up blood. A type of radiotherapy called SABR can be used in some situations – for example, when there is only one secondary cancer in the lung (or very few). 

  • Surgery

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

  • Tumour ablation

    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. It may be done under a general anaesthetic or using a local anaesthetic. Cryoablation (cryotherapy) is when extreme cold is used to destroy cancer cells.

You may be offered some treatments as part of a clinical trial.

Managing the symptoms of secondary lung cancer

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.

  • Laser treatment

    Laser treatment uses heat to destroy cancer cells. This can help relieve the symptoms. You usually have laser treatment under a general anaesthetic.

  • Stents

    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.

  • Internal radiotherapy

    If the cancer is blocking one of the airways, you may have a type of internal radiotherapy (brachytherapy). Most people have only 1 session of treatment. It is usually done in an operating theatre. 

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:

  • breathlessness
  • a cough
  • a dull, aching pain.

These symptoms can be relieved by carefully draining the fluid through a tube.

A cough

A cough is a common symptom. There are different treatments that can help a cough, including:

  • painkillers that you swallow
  • 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:

  • tablets
  • capsules
  • a liquid
  • skin patches
  • injections, usually under the skin.

Tell your doctor or nurse if your painkillers are not controlling the pain. Your doctor or nurse can increase the dose or give you a different drug. Or you may be given radiotherapy to control the pain.

Coughing up blood

You may notice some streaks of blood in your phlegm (sputum). This is not usually a problem. But if you notice larger amounts of blood, tell your doctor. You can have treatment to help control it – for example, radiotherapy. A drug called tranexamic acid can sometimes be helpful.

Your feelings

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:

  • anxiety
  • uncertainty
  • fear
  • anger.

These are all normal reactions.

Everyone has their own way of coping with difficult situations. You may find it helpful to talk to family or friends. Or you may prefer to seek help from people outside your 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:

About our information

  • References

    Below is a sample of the sources used in our secondary lung cancer information. If you would like more information about the sources we use, please contact us at  cancerinformationteam@macmillan.org.uk

    Morton DL, Yao K. Nonsurgical Treatment of Pulmonary Metastases. In: Kufe DW, Pollock RE, Weichselbaum RR, et al.Holland-Frei Cancer Medicine. 6th edition. Hamilton (ON): BC Decker; 2003.

    National Institute for Health and Clinical Excellence (NICE). Colorectal cancer NICE guideline Published: 29 January 2020

    Percutaneous radiofrequency ablation for primary and secondary lung cancers; NICE Interventional Procedure Guidance, December 2010

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editor, Dr David Gilligan, Consultant Clinical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

The language we use

We want everyone affected by cancer to feel our information is written for them.

We want our information to be as clear as possible. To do this, we try to:

  • use plain English
  • explain medical words
  • use short sentences
  • use illustrations to explain text
  • structure the information clearly
  • make sure important points are clear.

We use gender-inclusive language and talk to our readers as ‘you’ so that everyone feels included. Where clinically necessary we use the terms ‘men’ and ‘women’ or ‘male’ and ‘female’. For example, we do so when talking about parts of the body or mentioning statistics or research about who is affected.

You can read more about how we produce our information here.

Date reviewed

Reviewed: 01 November 2020
Next review: 01 November 2023

This content is currently being reviewed. New information will be coming soon.

Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

This means it is easy to use, up-to-date and based on the latest evidence. Learn more about how we produce our information.