Lung cancer that spreads to the brain may cause symptoms such as headaches and memory problems. Your outlook depends on factors like overall health and how well the cancer responds to treatment.

When cancer starts in one place in your body and spreads to another, it’s called metastasis. When lung cancer spreads to the brain, it means the primary lung cancer has created a secondary cancer in the brain.

Lung cancer is the most common cancer to spread to the brain.

About 15–20% of adults with non-small cell lung cancer (NSCLC) have brain metastases when they are first diagnosed. Up to 40% go on to develop brain metastases at some point during their lung cancer journey.

Brain metastases are more common in small cell lung cancer and lung cancer with certain mutations, such as:

  • EGFR-positive lung cancer
  • ALK-positive lung caner

Other common places lung cancer can spread to include:

  • bones
  • liver
  • adrenal glands
  • the other lung or the respiratory system

There are two main types of lung cancer:

Lung cancer spreads when cells from the original tumor break off and travel through lymph nodes or the bloodstream to other parts of the body.

While it’s easier for lung cancer to spread through the lymph vessels, it generally takes longer until the secondary metastatic cancer takes hold. It’s usually harder for the cancer to enter the bloodstream. Once it does, however, it spreads relatively quickly.

Lung cancer is the leading cause of cancer death for people worldwide.

Historically, life expectancy after a diagnosis of brain metastases from lung cancer has been generally unfavorable. But with advances in treatment, survival rates are improving.

According to a 2021 research review, the median survival rate for people whose lung cancer has spread to the brain is 12 months.

The Surveillance, Epidemiology, and End Results (SEER) database, maintained by the National Cancer Institute, provides 5-year survival rates for lung cancer based on how far the cancer has spread.

Distant lung cancer refers to lung cancer that has spread to distant parts of the body, including the brain.

  • The 5-year survival rate for distant non-small cell lung cancer is 8.2%.
  • The 5-year survival rate for distant small cell lung cancer is 3.6%.

Many factors can affect your outlook, including:

  • your sex
  • your ethnicity
  • your age and overall health
  • the type of lung cancer you have
  • specific genetic mutations in the tumor
  • how well the cancer responds to treatment

Usually, people who develop brain metastases farther out from their original diagnosis have a slightly higher survival rate than people whose lung cancer metastasizes to the brain earlier. But the difference is usually small.

Brain metastases don’t always cause symptoms. If they do, the symptoms may be focal or global.

Focal refers to symptoms related to the specific part of the brain where the tumor is. Focal symptoms may include:

Global symptoms affect your overall brain function. These may include:

  • headaches caused by swelling in the brain
  • decreases in memory, attention, and reasoning
  • nausea and vomiting
  • difficulty speaking
  • personality changes
  • seizures

If you or someone you know has lung cancer, it’s important to be informed about symptoms of brain metastases.

If you notice these symptoms, talk with a healthcare professional. You can discuss treatment options that may be available to provide comfort or increase quality of life and chances of survival.

To screen for metastatic brain cancer, doctors commonly use radiology tests such as:

Occasionally, a doctor may take a biopsy to determine if brain cancer is present.

When it comes to treating lung cancer brain metastases, the available options depend on several factors, such as:

  • the type of primary cancer that was diagnosed
  • the number, size, and location of brain tumors
  • the genetic behavior of the cancer cells
  • age and health
  • other attempted treatments

Treatment for metastatic brain cancer is dependent on the original type of lung cancer. When lung cancer spreads to the brain, it’s still considered lung cancer, not brain cancer.

The main types of treatment for brain metastases are:

Surgery

Surgery may be the first line of defense against brain metastases if:

  • there aren’t many tumors
  • the disease is controlled
  • you’re in otherwise good health

Stereotactic radiosurgery

This treatment is a high dose radiation therapy that targets a specific part of the brain. It’s usually used in people who have fewer tumors.

Whole brain radiation

Your doctor may recommend whole brain radiation if there are several tumors present. It can also follow surgery in some cases.

Immunotherapies and targeted therapies

Newer treatments, such as immunotherapy and targeted therapies, may be recommended as treatment options in some cases.

Targeted therapies that treat lung cancer may also treat brain metastases in people whose cancer has certain biomarkers, such as:

Immunotherapy is a type of treatment that uses your body’s own immune system to fight cancer cells. A 2020 study found that immunotherapy used in combination with radiation improved survival rates compared with radiation alone.

In the late stage of lung cancer that’s spread to the brain, the most frequent complications include:

During the final states, palliative care professionals try to optimize a person’s quality of life with psychological, technological, medical, and sociological considerations.

Brain metastases occur when cancer cells break off from the original tumor in the lung and travel to the brain.

While the past outlook for lung cancer that has spread to the brain has been typically unfavorable, advances in treatment options — including radiation, surgery, and immunotherapy — are improving survival rates.

If you have lung cancer that has spread to the brain, you may experience symptoms such as headaches, memory problems, or personality changes. Speak with a doctor right away if you notice any symptoms of brain metastases.