Lung metastases (secondary lung cancer): symptoms, tests and treatment

Where a cancer starts is called the primary cancer. Cancer Research UK explains that if some cancer cells break away from the primary cancer, they can travel through the bloodstream or lymphatic system to another part of the body and form a new tumour. This is called a secondary cancer or metastasis, and when it forms in the lung it is called secondary lung cancer or lung metastases.

Because the cells came from the original tumour, they keep its character. Cancer Research UK says that is important because the primary cancer tells your doctor which type of treatment you need. Macmillan makes the same point: the treatment is usually the one used for the primary cancer.

Cancer Research UK says any cancer can spread to the lung, with breast, bowel, kidney, testicular, bladder, melanoma skin cancer, bone cancer, soft tissue sarcomas and head and neck cancer among the most common. Macmillan lists bowel, breast, lung cancer spreading to the other lung, bladder, testicular, stomach, oesophageal, kidney, melanoma, sarcomas and head and neck cancers.

The phrase pulmonary nodules is also used. A pulmonary nodule is a small spot seen on a lung scan, and it can have several causes. Metastatic nodules are the ones that represent spread from another cancer, and a specialist team works out which is which.

Cancer Research UK lists the symptoms that secondary lung cancer might cause. Macmillan gives a similar list and adds that some people have no lung symptoms at all.

• A cough that does not go away or does not get better.

• Shortness of breath.

• Ongoing chest infections.

• Coughing up blood (haemoptysis).

• Chest pain or discomfort that does not go away.

• General symptoms such as tiredness, weight loss and loss of appetite.

• Fluid between the two layers covering the lung (a pleural effusion), which can cause breathlessness, a cough and chest pain.

Both sources stress that these symptoms can have other, more common causes, such as a chest infection. Cancer Research UK says that if you have any of them you should tell your doctor so that they can check, and Macmillan says always see your doctor, and that if you do not feel better after a treatment such as antibiotics, the doctor can do more tests.

If you have had cancer before, new breathlessness, cough or chest pain deserve prompt contact with your cancer team or GP rather than waiting for the next scheduled scan. Severe breathlessness or coughing up blood needs urgent assessment through 999 or A&E.

Macmillan says that if you have symptoms, you will usually begin by seeing your GP, who will examine you and refer you to a specialist if they think cancer could be the cause. Cancer Research UK lists the tests that may be used: chest X-ray, CT scan, PET scan and PET-CT scan.

Macmillan adds that a chest X-ray may be the first test, that a CT scan builds up a 3D picture, that a PET scan measures the activity of cells, and that you may need a biopsy, in which a sample of cells or tissue is taken from the lung and checked for cancer cells. If fluid has collected around the lung, it may be possible to drain some and test it for cancer cells.

Sometimes the secondary cancer is found before the primary. Macmillan says that if this happens you will have tests to find where the cancer started, and that occasionally doctors cannot find the primary cancer, which is called cancer of unknown primary.

Macmillan says a team of specialists, called a multidisciplinary team, meets to discuss the best treatment, and that the treatment depends on the primary cancer, your general health and your preferences. Cancer Research UK says secondary cancer cannot usually be cured and treatment usually aims to control the cancer and symptoms, and that some people may be too unwell to have treatment for their cancer. Macmillan notes that with certain cancers the aim may be to cure.

Macmillan describes treatments for specific problems. For breathlessness, there are treatments and drugs that can help. If a secondary cancer blocks an airway, laser treatment, a stent to hold the airway open or external radiotherapy may help. A pleural effusion can be relieved by carefully draining the fluid through a tube. A cough can be treated with different approaches, including some painkillers such as codeine or morphine that suppress cough, and nebulised drugs.

Macmillan says your doctor, cancer specialist or nurse will explain the different treatments and their side effects before you give your consent, and that you may be offered some treatments as part of a clinical trial.

Cancer Research UK acknowledges that most people worry about their outlook when they have a secondary cancer, and says that the outlook is usually difficult to predict and that this uncertainty can be hard to deal with. It advises speaking to your doctor, who can give more information about your outlook, and the factors it lists include how many parts of the body the cancer has spread to, how quickly it is growing and how it responds to treatment.

Support is available through your hospital team, a clinical nurse specialist and cancer charities. Cancer Research UK and Macmillan both run nurse helplines and online communities.