Lung metastasis is cancer that started in another part of the body and spread to the lungs. It’s sometimes called secondary lung cancer or metastatic lung tumours. Lung metastasis is not the same as cancer that starts in the lung (called primary lung cancer).
Some kinds of cancer are more likely to spread to the lung than others. The most common cancers that spread to the lung are:
- head and neck (such as laryngeal)
- bone (such as osteosarcoma)
- soft tissue sarcoma
Cancer can spread to anywhere in the lungs. Sometimes there is only a single tumour in one lung. Sometimes there are many metastases in one or both lungs. Most lung metastases develop near the edges of the lungs and in the lower lobes. Cancer can also spread to areas outside of the lung, such as the pleura and mediastinum.
Lung metastases may not cause any symptoms at first. The symptoms of lung metastases vary depending on the number of tumours and where they are in the lungs. Other health conditions can cause the same symptoms as lung metastases.
See your doctor if you have these symptoms:
- a cough that doesn’t go away
- shortness of breath
- frequent chest infections
- coughing up blood
- pain or discomfort in the chest
- weight loss
The following tests may be used to diagnose lung metastases. Many of the same tests can help your healthcare team plan treatment and monitor lung metastases.
Health history and physical exam
Your health history is a record of your symptoms, risk factors and all the medical events and problems you have had in the past. In taking a health history, your doctor will ask questions about a personal history of symptoms that suggest lung metastases.
A physical exam allows your doctor to look for any signs of lung metastases. During a physical exam, your doctor may listen to your lungs.
Find out more about physical exam.
A complete blood count (CBC) and electrolyte panel may be done to check your general health and find out how well certain organs are working. The level of oxygen in your blood, or oxygen saturation, may also be measured to check if your lungs are bringing enough oxygen into your body.
Sometimes tumour marker tests are done if you have had cancer before. These tests measure the amount of a specific protein in the body. An increase in the level of tumour markers in the blood may mean that the primary cancer has come back and spread to the lungs. Examples of tumour markers that may be measured include:
- carcinoembryonic antigen (CEA) if you had colorectal cancer
- alpha-fetoprotein (AFP) and human chorionic gonadotropin (HCG or b-HCG) if you had testicular cancer
Imaging tests are an important part of diagnosing lung metastases. It is common for people to have one or more imaging tests when the doctor thinks that cancer may have spread to the lungs. These tests include the following.
Chest x-ray is usually the first test done to try to find out what is causing symptoms like a cough and shortness of breath. Doctors use chest x-ray to look for any lung tumours.
Computed tomography (CT) scan of the chest is a common test used to check for lung metastases. It provides more detailed images of lung tumours than a chest x-ray, including the size and location of the tumours. It can also be used to check for cancer in nearby lymph nodes.
Positron emission tomography (PET) scan of the lungs or the whole body may be done. It may be used to check if lung tumours are cancerous or not.
A bronchoscopy is a test used to look inside the trachea (windpipe), bronchi (large airways of the lungs) and lungs using an endoscope. It is often done to find out why a person is coughing up blood. A biopsy can be taken during a bronchoscopy.
Find out more about bronchoscopy.
A biopsy is the removal of cells or tissues so they can be examined under a microscope. It is sometimes done when the doctor finds lung tumours with imaging tests. If you have had cancer, doctors may be able to diagnose lung metastasis with imaging tests alone. If you haven’t had cancer, doctors may do a biopsy to find out if the cancer started in the lung or spread to the lung.
Doctors usually use an imaging test like a CT scan to help locate the specific area to biopsy. The types of biopsies used to diagnose lung metastasis include:
- needle biopsy through the chest wall (called transthoracic needle aspiration biopsy)
- endoscopic biopsy during bronchoscopy (called transbronchial biopsy)
- surgical biopsy
Find out more about biopsy.
If lung metastases are found before the primary cancer is diagnosed, the doctor may order tests to find out where the cancer started. Other tests may also be used to check for metastatic cancer in other parts of the body. These tests may include:
- mammography to check for breast cancer
- CT scan of the abdomen and pelvis to check for colorectal cancer and liver metastases
- mediastinoscopy to check lymph nodes in the middle of the chest
- ultrasound to check for testicular cancer
Treatments and supportive therapies
If you have lung metastases, your healthcare team will create a treatment plan just for you. It will be based on your needs and usually includes a combination of different treatments. Treatments can control and slow the growth of lung metastases, but the metastases usually don’t go away completely. They can also manage or prevent problems caused by lung metastases. These are sometimes called supportive therapies.
When deciding which treatments and supportive therapies to offer for lung metastases, your healthcare team will consider:
- where the cancer started
- your symptoms
- the size, number and location of metastases in the lungs
- if the cancer has spread to other parts of the body
- cancer treatments you’ve already received
- the general health of your lungs
- your personal preferences
You may be offered the following treatments and supportive therapies for lung metastases.
Chemotherapy is the most common treatment for lung metastases. It is used to help shrink and control the growth of cancer. Chemotherapy is sometimes used along with other treatments such as surgery and targeted therapy.
Chemotherapy uses drugs that circulate throughout the body to destroy cancer cells. The drugs are usually given intravenously (through a needle into a vein) or orally (as a pill by mouth).
The type of chemotherapy drug or combination of drugs used depends on where the cancer started and if you’ve had chemotherapy before. The drugs, dose and schedule will vary for each person.
Side effects of chemotherapy will depend mainly on the type of drug, the dose and how it’s given. Common side effects of many chemotherapy drugs are low blood cell counts (called bone marrow suppression), nausea and vomiting, mouth problems and bowel problems.
Hormonal therapy may be used to control the growth of cancer and help relieve symptoms. It is given for some types of cancer that have spread to the lungs, such as breast and thyroid cancers.
Hormonal therapy is a treatment that adds, blocks or removes certain hormones to slow or stop the growth of cancer cells that need hormones to grow. Drugs, surgery or radiation therapy can be used as hormonal therapy.
Side effects will depend mainly on the type of hormonal therapy. Common side effects of many types of hormonal therapy are hot flashes and weight gain.
Targeted therapy uses drugs that find and attach to specific substances (such as proteins) on the surface of or inside cancer cells. These substances help send signals that tell cells to grow or divide. The targeted therapy drugs block the substances to stop or slow the growth and spread of cancer cells.
Targeted therapy is most often used along with chemotherapy. It may be used to control the growth of lung metastases for some types of cancer, including:
- bevacizumab (Avastin) or cetuximab (Erbitux) is used for colorectal cancer
- trastuzumab (Herceptin) is used for HER2-positive breast cancer
- ipilimumab (Yervoy) is used for melanoma
- sunitinib (Sutent) is used for kidney cancer
- pazopanib (Votrient) is used for soft tissue sarcoma
Targeted therapy is given intravenously (through a needle into a vein) or orally (as a pill by mouth).
Side effects depend mainly on the type and dose of the drug. Common side effects of many targeted therapy drugs are skin problems, flu-like symptoms and fatigue. Most side effects go away on their own or can be treated. Tell your healthcare team if you have these side effects or others you think might be from targeted therapy.
Find out more about targeted therapy.
Immunotherapy is a type of biological therapy that uses the immune system to help destroy cancer cells. It may be used to treat some cancers that have spread to the lungs, such as melanoma.
Immunotherapy is usually given intravenously (through a needle into a vein). Examples of immunotherapy that may be used to treat lung metastases include:
- interleukin-2 (Aldesleukin, Proleukin)
- interferon-alfa-2b (Intron A)
Side effects of immunotherapy depend mainly on the type and dose of the drug. Common side effects of many immunotherapy drugs are flu-like symptoms and fatigue.
Find out more about immunotherapy.
Surgery is most often used for colorectal cancer, bone cancer or soft tissue sarcoma that has spread to the lungs. Lung resection may be used to treat lung metastases when cancer is only in one small part of the lung (called isolated, or limited, metastases). This surgery removes part (usually a wedge-shaped piece) of a lung. The goal of a lung resection is to completely remove the metastases so that there are no cancer cells in the healthy tissue removed along with the tumour (called negative surgical margins). Only part of the lung is removed so that the lungs will still work as normally as possible after surgery.
A lung resection is done by a surgeon who specializes in lung surgery (called a thoracic surgeon). It is usually done by making a cut, or incision, in the chest (called open lung resection). Video-assisted thoracoscopic surgery (VATS) or video-assisted thoracoscopy may be done in some cases. These techniques can be used when there are only a few small tumours.
Not everyone with lung metastases can have surgery. Doctors will decide if surgery is an option based on the size, number and location of tumours, how well the primary cancer is controlled, your overall health and other factors.
Side effects of surgery will depend mainly on the type of surgery done, the amount of lung removed and your overall health. Some side effects of a lung resection are pain, bleeding, wound infection and lung infection.
Ablation therapy is a procedure that removes or destroys cells or tissues with heat, chemicals or other techniques. Different types of ablation therapy may be used to treat lung metastases. They are usually used to treat small tumours and control symptoms when surgery can’t be done because it’s not safe or possible.
Ablation therapies for lung metastases are done by surgeons with specialized experience. They may not be available at all treatment centres.
The following ablation therapies may be used to treat lung metastases. Side effects will depend mainly on the type of procedure done and how much of the lungs are treated.
Radiofrequency ablation (RFA) uses electrical currents to create heat that destroys cancer cells. A needle is placed directly into a lung tumour. The surgeon will use an imaging test, such as ultrasound or CT scan, to guide the needle into the tumour. Electrical currents are passed through the needle. These currents heat and destroy the tumour.
Laser therapy, or laser surgery, uses a laser (a high-intensity beam of light) to make bloodless cuts in tissue. The doctor uses thoracoscopy to locate the tumour and direct the laser beam at it. The laser beam heats and destroys the cancer cells. Laser therapy is usually used when cancer is blocking the windpipe (called the trachea) or a large airway (called a bronchus).
Radiation therapy is not used very often to treat lung metastases. In some cases, external beam radiation therapy may be used to relieve symptoms like difficulty breathing, coughing and bleeding.
During external beam radiation therapy, a machine directs a beam of radiation through the skin to the lungs. How long external beam radiation is used depends on the goal of treatment, the number of tumours, how many areas of the lungs are affected by cancer and other factors. A short course of radiation therapy is usually given for lung metastases. Radiation therapy is given once a day for 5 days. Sometimes only a single treatment may be given.
Stereotactic body radiation therapy, or stereotactic ablative radiotherapy, delivers a high dose of radiation in a very targeted way. The radiation goes directly to the tumour so that it doesn’t affect healthy lung tissue around the tumour. How many sessions of stereotactic radiation therapy are used depends on the size, location and number of metastases being treated, as well as other factors.
Side effects will depend mainly on the type of radiation therapy, the amount of the lungs being treated and the length of treatment.
Thoracentesis may be used to treat an abnormal buildup of fluid in the space between the lungs and chest wall (called pleural effusion).
During thoracentesis, the doctor inserts a hollow needle through the skin and into the space between the lungs and the chest wall (called pleural cavity). The doctor uses the needle to drain extra fluid from the chest cavity. After the extra fluid is drained, the doctor may put a substance into the pleural cavity to help stop the fluid from building up again. This procedure is called pleurodesis.
Oxygen therapy gives you extra oxygen through a mask over your mouth or through tubes in your nostrils. It makes sure you get enough oxygen if you have trouble breathing.
Lung metastases can grow inside and block the airways in the lungs. They can also put pressure on structures outside the airway and make it narrow. The doctor may place a stent, or small tube, inside an airway to hold it open. It is inserted into the airway using bronchoscopy. The stent can usually stay in the airway permanently.
Living with lung metastases
Adjusting to life with lung metastases can take time. A person with lung metastases may have concerns about the following.
Difficulty breathing (also called shortness of breath, or dyspnea) is a common problem in people with lung metastases. It can be caused by:
- a tumour blocking or narrowing an airway
- cancer causing pressure on structures outside of an airway
- pleural effusion
- low levels of oxygen in the blood (called hypoxemia)
- an infection in one or both lungs (called pneumonia)
- low red blood cell count (called anemia)
- anxiety and stress
How difficulty breathing is managed depends on the cause. Treatments for difficulty breathing may include:
- oxygen therapy
- medicines that open your airways
- anti-anxiety medicines
- stent placement
- thoracentesis when there is pleural effusion
- relaxation and breathing exercises
Find out more about difficulty breathing.
A diagnosis of advanced cancer can lead to questions about survival. There is no way of knowing exactly how long someone will live with lung metastases. It depends on many factors, including the type of cancer, the number of lung metastases and if surgery can be done. Survival with lung metastases is sometimes measured in months. But some people can survive for many years, especially if surgery is done to remove the metastases. Some people may live much longer than expected, while others may die sooner than expected.
The best person to talk to about survival is the doctor. The doctor may be able to estimate survival based on what they know about a person and the type of cancer, but it’s not an exact science.
Find out more about living with advanced cancer.
A part or section of an organ that is separated by a boundary such as a membrane or ligament.
Examples include the lobes of the liver, lungs or brain.
The thin layer of tissue that covers the lungs and lines the chest cavity. It protects and cushions the lungs and produces a fluid that acts like a lubricant so the lungs can move smoothly in the chest cavity.
The space in the chest between the lungs, breastbone and spine that contains the heart, great blood vessels, thymus, trachea (windpipe), esophagus and lymph nodes.
A procedure that uses an endoscope (a thin, tube-like instrument with a light and lens) to examine or treat organs or structures in the body.
Cells or tissue may be removed for examination under a microscope. Doctors may also use endoscopy to control bleeding or remove tumours and foreign bodies.
Specialized endoscopies are named for the organ or structure they examine or treat.
A procedure that uses an endoscope (a thin, tube-like instrument with a light and lens) to examine or treat the organs in the mediastinum (the space between the lungs) and nearby lymph nodes.
Cells or tissue may be removed for examination under a microscope. Doctors often use mediastinoscopy to get a sample of tissue from the lymph nodes on the right side of the chest.
The type of endoscope used for this procedure is called a mediastinoscope.
I’m extremely grateful to the Canadian Cancer Society for funding my research with an Innovation Grant.
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