Metastatic lung cancer begins in the lungs and spreads to other areas. The spread of cancer is called metastasis.

By the time lung cancer is metastatic, it is in a late stage and can be challenging to treat. But the outcome varies from person to person.

Lung cancer often has no symptoms in its early stages. Older estimates, from 2010, suggest that in almost 39% of people with non-small cell lung cancer, the cancer had metastasized by the time it was diagnosed.

“Metastatic” refers to a stage, not a form of cancer. And the name of cancer does not change when the disease affects a new area. For example, lung cancer that spreads to the liver is called metastatic lung cancer, rather than liver cancer.

In this article, we look at how lung cancer spreads to other organs, the effects on the body, and how doctors treat it.

What is the difference between small-cell and non-small cell lung cancer?

Metastatic cancer has spread from one area of the body to another. If cancer affects the bones of a person with lung cancer, it may have spread from the lungs to the bones. This is metastatic lung cancer.

Or, a person with lung cancer may develop new cancer that begins forming in the bones. In this case, the person has lung cancer and bone cancer.

Metastatic lung cancer cells have the same features as the original lung cancer cells. A pathologist can see this if they examine the cancerous tissue under a microscope.

Sometimes, however, doctors do not diagnose cancer before it spreads, and it is not possible to identify where it first developed.

A person may have effective treatment for one type of cancer, then develop a second cancer elsewhere in the body. This is not metastatic cancer.

In other cases, a person receives treatment for cancer in one area, and then their cancer spreads, becoming metastatic, after several years. This can occur even if tests no longer detect the original tumor.

Lung cancer may develop again in the same lung after successful treatment. This is called recurrent lung cancer.

If cancer develops in the other lung, it is metastatic if it has spread. Or, it may be a new, separate case of lung cancer.

Learn about the types of lung cancer and how quickly they spread.

Metastatic cancer does not always cause symptoms. If they occur, the specific type of symptom depends on the affected area of the body.

Below, learn about areas that metastatic lung cancer commonly affects and some of the symptoms that may arise.

Adrenal glands

If cancer has spread to the adrenal glands, this usually causes no symptoms. However, if the tumor is large, it may cause pain in the back or abdomen.

If cancer affects at least 90% of both glands, it can cause adrenal insufficiency, which can lead to a loss of appetite, fever, weakness, fatigue, nausea, vomiting, and other symptoms.

Bones

Around 30­–40% of people with advanced lung cancer develop bone metastases. In this case, pain is the main symptom, and the risk of fractures increases.

Brain

About 20–35% of people with non-small cell lung cancer develop brain metastases. Headaches, confusion, tiredness, nausea, and weakness are symptoms.

Liver

Appetite loss, nausea after eating, and pain under the right ribs can indicate liver cancer. Jaundice is another symptom. This involves yellowing of the skin and the whites of the eyes.

Lymph nodes

Enlarged lymph nodes in the armpit, neck, and stomach can suggest that lung cancer has spread.

It is worth noting, however, that these nodes also swell in response to other health issues.

Here, learn about the different types of lung cancer.

Most cells have a limited life cycle. As they die, new ones form. Lung cancer develops when cells in the lungs continue to multiply, without dying.

The excess cells form a tumor. As it grows, it needs more space, and it starts spreading to other areas. At this point, the cancer becomes metastatic.

Cancer cells spread in two ways, either by entering nearby tissue or by breaking away from the tumor and traveling through the bloodstream or lymphatic system to other parts of the body.

The National Cancer Institute note that cancer cells can:

  • grow on or into nearby tissue and form a new tumor
  • grow through the walls of nearby blood vessels
  • stop inside blood vessels
  • increase the growth of blood vessels, which supply additional blood and oxygen to the tumor

Where does it spread?

If lung cancer spreads, it typically invades areas such as the:

  • adrenal glands
  • other lung
  • bones
  • brain
  • liver
  • lymph nodes

What are some other complications of lung cancer?

Testing for metastases involves checking the areas where lung cancer typically spreads.

Diagnostic testing involves:

Treatment for lung cancer that has spread focuses on controlling the growth and relieving the symptoms. Cancer that has metastasized throughout the body can be difficult to eliminate.

The treatment options depend on the type of lung cancer, the location of the metastases, previous treatment, and the person’s overall health.

Options include:

  • chemotherapy
  • biological therapy
  • radiation therapy
  • laser therapy, if part of a tumor is blocking an airway
  • other medications to manage symptoms, such as pain

Preventing metastasis

Some cancer treatments may help stop or slow metastasis by making conditions less suitable for the growth of cancer cells.

Anti-angiogenic drugs, for example, can stop tumors from growing their own blood vessels. Cutting off the supply of blood to the tumor can slow or prevent its growth.

Tyrosine kinase inhibitors, or TKIs, prevent or reduce tumor growth by blocking growth signals within or between cancerous cells.

Meanwhile, scientists are investigating other ways to prevent cancer from spreading.

Healthy cells contain adhesion molecules that allow them to stick together. A 2019 study suggests that the loss of function in adhesion molecules may contribute to metastasis.

Scientists have also discovered that cancer cells secrete substances called exosomes that stimulate the cells to move. Research into the role of these exosomes in metastasis is ongoing.

It is not always possible to prevent lung cancer or keep it from spreading.

However, avoiding things that increase the risk of developing lung cancer can help. Smoking, for example, is a preventable risk factor.

Also, treatment is more likely to be effective in the early stages, so receiving a diagnosis and treatment early may prevent the cancer from spreading.

However, receiving an early diagnosis can be challenging because there are often no symptoms in the early stages. This is why screening is so important — it can detect lung cancer while it is still relatively easy to treat.

Here, find vital tips for quitting smoking.

People with a high risk of lung cancer may wish to consider screening. It may be appropriate for those who:

  • are 55–74 years of age
  • currently smoke or stopped smoking in the last 15 years
  • have smoked a pack a day for 30 years, two packs a day for 15 years, or the equivalent

Screening can help detect changes early, when effective treatment can reduce or eliminate the cancerous cells before they spread.

However, not everyone has access to screening facilities.

Read more about the stages of lung cancer.

The rate at which lung cancer spreads depends on various factors, including the type of cancer and the person’s overall health. These all affect the person’s outlook.

According to the American Cancer Society, people with non-small cell lung cancer that has spread to distant areas have a 7% chance of surviving another 5 years after their diagnosis. For those with small-cell lung cancer that has spread to distant areas of the body, this figure is around 3%.

Treatments can help manage the symptoms and improve the person’s quality of life. In some cases, they may also slow the development of the cancer and help extend the person’s lifespan.

Learn more about the prognosis for late-stage lung cancer.

Treatments and lifestyle adjustments can help enhance the comfort and quality of life of someone with metastatic lung cancer.

The support of friends, family, and healthcare providers can help a person manage the emotional impact and practical challenges of living with cancer.

Specifically, a person may benefit from:

  • seeking support from friends and family
  • joining a cancer support group
  • attending counseling
  • regularly discussing symptoms and options with members of the healthcare team

Also, a healthcare professional can often help locate appropriate counseling services and support groups.

In addition, the American Lung Association provide a directory of support groups and other resources.