When cancer develops, it typically forms in one area or organ of the body. This area is known as the primary site. Unlike other cells in the body, cancer cells can break away from the primary site and travel to other parts of the body.

Cancer cells can move in the body through the bloodstream or the lymph system. The lymph system is made up of vessels that carry fluids and support the immune system. When cancer cells travel to other organs in the body, it’s called metastasis.

Metastatic lung cancer is a life-threatening condition that develops when cancer in another area of the body metastasizes, or spreads, to the lung. Cancer that develops at any primary site can form metastatic tumors. These tumors are capable of metastasizing to the lungs. Primary tumors that commonly spread to the lungs include:

Metastatic lung cancer doesn’t always cause symptoms. When symptoms do develop, they can be difficult to identify. This is because the symptoms may be similar to health conditions other than cancer.

The symptoms of metastatic lung cancer can include:

  • a persistent cough
  • coughing up blood or bloody phlegm
  • chest pain
  • shortness of breath
  • wheezing
  • weakness
  • sudden weight loss

For cancer cells to metastasize, they must go through several changes. First, the cells have to break away from the primary site and find a way to enter the bloodstream or lymph system. Once they’re in the bloodstream or lymph system, the cancer cells must attach themselves to a vessel that will allow them to move to a new organ. In the case of metastatic lung cancer, the cancer cells travel to the lungs.

When the cells arrive at the lung, they’ll need to change again in order to grow in the new location. The cells must also be able to survive attacks from the immune system. All of these changes make metastatic cancer different from the primary cancer. This means that people can have two different types of cancer, making treatment more difficult.

Your doctor will perform a physical exam and order various diagnostic tests if metastatic lung cancer is suspected.

Diagnosis of metastatic lung cancer can be confirmed through the following:

  • a chest X-ray, which creates detailed images of the lung
  • a CT scan, which produces clear, cross-sectional pictures of the lung
  • a lung needle biopsy, which allows your doctor to remove a small sample of lung tissue for analysis
  • a bronchoscopy, which allows your doctor to directly visualize all the structures that make up your respiratory system, including the lungs

The goal of treatment is to control the growth of the cancer or to relieve any symptoms. There are numerous different treatments available, and your specific treatment plan will depend on various factors, including:

  • your age
  • your overall health
  • your medical history
  • the type of primary tumor
  • the location of the tumor
  • the size of the tumor
  • the number of tumors

Chemotherapy is often used to treat metastatic lung cancer. This is an aggressive form of chemical drug therapy that helps destroy cancerous cells in the body. It’s the preferred treatment option when the cancer is more advanced and has spread to other organs in the body.

In some cases, surgery may also be performed to remove the metastatic tumors in the lung. This is usually done if someone already had their primary tumor removed or if the cancer has only spread to limited areas of the lung.

Other treatments that may be recommended by your doctor include:

  • radiation therapy, which uses high-energy radiation to shrink tumors and kill cancer cells
  • laser therapy, which uses high-intensity light to destroy tumors and cancer cells
  • the placement of stents, or tiny tubes, in the airways to keep them open

Experimental treatments for metastatic lung cancer are also available. Heat probes can be used to destroy cancer cells in the lungs. Chemotherapy drugs may also be applied directly to the affected area of the lung containing the metastatic tumor.

Your long-term outlook will depend on the size and location of your primary tumor. It will also depend on how much the cancer has spread. Certain cancers that metastasize to the lungs can be very treatable with chemotherapy. Primary tumors in the kidney, colon, or bladder that metastasize to the lungs may sometimes be completely removed with surgery.

In most cases, metastatic lung cancer can’t be cured. However, treatments may help prolong your life and improve the quality of your life.

It’s very difficult to prevent metastatic lung cancer. Researchers are working on preventive treatments, but nothing is common practice yet. One step toward preventing metastatic cancer is prompt and successful treatment of your primary cancer.

It’s important to have a strong support network that can help you deal with any stress and anxiety you may be feeling if you have a diagnosis of metastatic lung cancer. You may want to speak with a counselor or join a cancer support group where you can discuss your concerns with others who can relate to what you’re going through. Ask your doctor about support groups in your area. You can also find information on support groups on the National Cancer Institute and the American Cancer Society websites.