How lung metastases differ from primary lung cancer

Cancer that metastasizes to the lungs means cancer It has spread to the lungs from another part of the body. Another term for metastatic cancer of the lung is secondary cancer of the lung, because the primary cancer is the part of the body where the cancer begins or originates.

For example, if breast cancer spreads to the lungs, it is called breast cancer that has metastasized to the lungs, or breast cancer that has metastasized to the lungs. It wouldn’t be called lung cancer because if you looked at metastatic tumors under a microscope, you would see that they were cancerous breast cells, not cancerous lung cells.

Also important, if you’re looking for information about cancer that started in the lungs and spread to other parts of the body, check for metastatic (stage 4) lung cancer.

cancer that may metastasize

You might be surprised to learn that lung metastases are common. While almost all cancers can spread to the lungs, some cancers are more likely to do so than others. Therefore, the most common types of cancer that metastasize to the lungs include:

  • Bladder Cancer
  • breast cancer
  • colon cancer
  • kidney cancer
  • melanoma
  • ovarian cancer
  • Pancreatic cancer
  • prostate cancer
  • rectal cancer
  • stomach cancer
  • Thyroid cancer
  • uterine cancer

Lung metastases also frequently occur in sarcomas, a relatively rare cancer. Lung metastases occur in up to 20% of soft tissue sarcomas and up to 40% of osteosarcomas.

Sometimes, healthcare providers are unable to determine where the cancer originated. In this case, they called the cancer of unknown origin and metastasized to the lungs.

How Cancer Spreads

While normal cells can be considered “sticky” because they have adhesion molecules that hold them together, cancer cells are different. They don’t make these adhesion molecules, allowing them to break free and travel as they please.

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When traveling, cancer cells may extend directly to the lungs, such as cancers that start in the esophagus or chest wall. But most cancer cells spread indirectly through three possible ways:

  • Blood flow (called hematogenous spread): Cancer cells may “leak” into small blood vessels near the tumor, which are then transported to the lungs through the pulmonary artery.
  • Lymphatic system: Tumor cells may infiltrate small lymphatic vessels and spread along lymphatic pathways, including lymph nodes.
  • Pleural spread and airway spread: The pleura refers to the membrane surrounding the lungs. This type of spread is usually limited to lung tumors and is less common.


Lung metastases usually cause no symptoms. In this case, metastases can be found on radiological tests, such as CT scans, to look for the presence of cancer spread.

If symptoms occur, they often resemble those of primary lung cancer, such as:

  • persistent cough
  • coughing up blood (called hemoptysis) or bloody phlegm
  • chest, shoulder and back pain
  • shortness of breath
  • low blood oxygen levels (called hypoxemia)
  • pleural effusion

Because metastatic cancer means the primary cancer has spread throughout the body, general symptoms such as fatigue, unexplained weight loss, and decreased appetite are also common.


If your healthcare provider suspects you have lung metastases, she may consider doing several tests. These include:

  • Chest X-ray (chest X-rays can easily miss small metastases)
  • chest CT scan
  • PET scan
  • Lung biopsy (needle biopsy or open lung biopsy)
  • If pleural effusion is present, analyze pleural effusion
  • Bronchoscopy
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Results from these imaging studies may provide sufficient evidence of metastasis, although biopsy may be required to confirm the diagnosis.


Treatment of cancer that has metastasized to the lungs often depends on the primary cancer or the origin of the cancer. These treatments may include hormone therapy, targeted therapy, chemotherapy, immunotherapy, or a combination of treatments.

Chemotherapy is usually the treatment of choice and is usually given as palliative care, a treatment that prolongs survival and reduces symptoms. Palliative care is not designed to cure cancer. Even so, in rare cases, such as testicular cancer that metastasizes to the lungs, chemotherapy may be curative. Clinical trials of inhaled chemotherapy are currently underway, with the hope that delivering the chemotherapy directly to the lungs would be effective with fewer side effects.

Surgery for lung metastases (called metastases resection) is occasionally considered. For this to be effective, your healthcare provider will want to make sure that your primary tumor is completely removed and that all metastases can be removed technically (surgically). In this case, metastases removal may improve your survival rate.

In addition to surgery, stereotactic radiation therapy (SBRT), also known by terms like “electronic knife,” is sometimes used to treat cancer from other organs that has metastasized to the lungs.


Unfortunately, cancer that has spread to the lungs (called stage 4 cancer) is often incurable. That said, it is usually very treatable, and your healthcare provider will discuss with you treatments that may prolong your life and give you the best quality of life.

Survival rates, defined as the percentage of people whose cancer is diagnosed five years or more, varies widely depending on the primary tumor. For example, tumors that have spread to the lungs, such as testicular cancer, have the highest survival rate (74% at 5 years).

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The upside here is that the prognosis for lung metastases may improve in the near future. There are already some stage 4 cancers that respond to treatments such as immunotherapy, which was unheard of a few years ago.

VigorTip words

Lung metastases, or metastatic cancer, occur when cancer that originated in other parts of the body, such as the breast or bladder, spreads to the lungs. Most people with lung metastases are asymptomatic, but they may experience cough, chest pain, or hemoptysis.

Lung metastases are often treated as part of the treatment regimen for the primary cancer, and while metastatic cancer is often incurable (with uncommon exceptions), treatment can prolong life and improve quality of life by managing symptoms.

Frequently Asked Questions

  • Where does lung cancer spread?

    Metastatic lung cancer can spread to any structure or organ in the body, including the brain, liver, lymph nodes, and adrenal glands. It is also known as stage 4 non-small cell lung cancer (NSCLC). Doctors will use tests and biopsies to check where non-small cell lung cancer has spread.

  • What are the symptoms of lung metastases?

    Symptoms of lung metastases include chest pain, frequent coughing, coughing up blood, fluid buildup around the lungs, decreased appetite, weight loss, and shortness of breath. Depending on the symptoms, certain types of medications may be prescribed to relieve symptoms. For recurrent shortness of breath, controlled opioids may be prescribed. If none of these work, anti-anxiety medication may help.