When Lung Cancer Spreads to the Brain

Lung cancer frequently spreads, or metastasizes, to other parts of the body. One of the most dangerous areas it can travel to is the brain. Known as brain metastases, lung cancer that spreads to the brain raises grave concerns about life expectancy.

Unfortunately, these metastases are fairly common. Up to 7% of people already have cancer cells in the brain when they are first diagnosed with non-small cell lung cancer (NSCLC), and 20% to 40% of those with NSCLC will develop the complication at some point.

Brain metastases occur in stage 4 lung cancer. Once NSCLC is this advanced, the prognosis is poor, with life expectancy usually being under a year. However, improved diagnostic tools, more effective treatments, and a clearer understanding of how to manage symptoms have led more people to extend their lives.

Brain Metastases Symptoms

Small cell lung cancer is often difficult to diagnose in the early stages and, as a result, may spread to the brain before a lung cancer diagnosis is even made. Non-small cell cancers can also spread to the brain but tend to do so later in the course of the disease after the primary tumor has been discovered.

Because it's so easy to miss small growths, it's important for those with lung cancer to watch for symptoms of brain metastases.

Symptoms can vary based on the type of lung cancer and where tumors are located in the brain, but common problems include:

• Headaches
• Nausea and vomiting
• Seizures
• Speech problems
• Muscle spasms
• Abnormal smells or tastes
• Numbness or tingling in parts of the body
• Fatigue or muscle weakness
• Difficulty with balance or movement
• Vision changes, including loss of vision or double vision

Some symptoms are related to tumors putting pressure on the skull and brain tissue. These are typically worse when first waking up in the morning.

Many people with secondary brain cancer will have no symptoms and only discover they have the condition after undergoing a brain scan for an unrelated condition.

Diagnosis

If healthcare providers suspect that your lung cancer has spread to your brain, they will order imaging tests such as a computed tomography (CT) scan, which uses X-rays to create diagnostic images, or magnetic resonance imaging (MRI), which does the same with magnetic waves.

While an MRI is considered more accurate, it cannot be used if you have certain metal implants (including non-safe pacemakers).

If a suspicious lesion is found but the diagnosis is uncertain, a biopsy may be performed to obtain a tissue sample for evaluation.

Leptomeningeal Metastases

Leptomeningeal metastases (leptomeningeal carcinomatosis) tend to be a late complication of advanced lung cancer. Healthcare providers are seeing this condition more often as people with lung cancer live longer lives.

Leptomeningeal metastases occur when cancer cells invade the cerebrospinal fluid—the clear, colorless liquid that flows through the brain and spinal cord to deliver nutrients and provide a cushion against injury. The cancer cells can thrive in this nutrient and oxygen-rich fluid.

Leptomeningeal metastases often involve multiple neurological symptoms. This is a terminal stage of cancer with an average survival rate of just six to eight weeks.

However, new methods of delivering chemotherapy directly into cerebrospinal fluid have improved the rate to between three and nine months. There has also been some success with drugs that are traditionally used to target genetic mutations in cancer cells, such as treatments for EGFR-positive lung cancer.

Treatment

Essentially, treatments for brain metastases are not considered possible cures. They aim to reduce pain and increase how long you live with lung cancer that has spread to the brain. However, that doesn't mean that they can't make a significant difference.

Studies show that people who are treated with appropriate therapy for ALK-positive lung cancer (related to a specific gene mutation) with brain metastases, for example, have a survival rate of 6.8 years. That's a huge improvement over the estimated 12-month survival rate for lung cancer that has spread to the brain.

The treatment of brain metastases depends on a number of factors including how much of the brain is involved and your overall health. Which methods are used is usually determined by how best to control symptoms.

For instance, steroids such as Decadron (dexamethasone) are used to control any swelling of the brain. Anticonvulsive medications are sometimes used to control seizures.

Before pursuing this treatment, it's important to consider whether the seizures are a side effect of another treatment and to determine whether the anti-seizure drug might interact with other medications you're taking. Discuss these points with your healthcare provider.

Chemotherapy

Many chemotherapy drugs are ineffective in treating brain metastases due to the presence of the blood-brain barrier, a tight network of capillaries that serves to keep toxins (including chemotherapy drugs) out of the brain. Chemotherapy may, however, reduce the size of tumors in the lungs and, therefore, limit their ability to spread to the brain.

Targeted Therapy

Targeted drugs for EGFR mutations, ALK rearrangements, ROS rearrangements, and other genetic mutations are sometimes able to penetrate the blood-brain barrier. Some of the newer drugs for EGFR mutations as well as therapies for ALK rearrangements appear to be very effective at treating brain metastases.

Like chemotherapy, these drugs also control the primary tumor and, thus, limit its ability to spread further.

Immunotherapy

Some drugs classified as immunotherapy are able to cross this blood-brain barrier as well. When a single or only a few brain metastases are present, immunotherapies can help with long-term control of the disease.

These therapies are still fairly new, but several medications show promise in their ability to reduce brain metastases. Cancer cells make checkpoint proteins that prevent your immune system from attacking the malignancy, but studies show that immunotherapy drugs can inhibit these proteins, allowing your body to fight the cancer.

Whole-Brain Radiotherapy

If scans show that there are multiple brain metastases present (as few as four or more than 20, depending on your circumstances), your healthcare provider may recommend whole-brain radiotherapy.

This treatment has a number of drawbacks, but it's considered appropriate for those who are at risk for stroke or other serious complications related to brain metastases. It can also be used after surgery to limit the spread of cancer.

With this treatment, radiation is administered to the entire brain—usually over the course of many weeks. Common side effects can include memory loss (especially verbal memory), skin rash, fatigue, nausea and vomiting, hearing loss, and seizures. Radiation oncologists often recommend medication to help alleviate symptoms.

While not designed to cure cancer, at least 75% of people undergoing whole-brain radiotherapy will notice some improvement in symptoms, and it's been shown to improve overall survival from one month with no treatment to two to seven months with treatment.

Stereotactic Radiotherapy

Stereotactic radiosurgery (SRS) is a type of high-dose radiation given to a specific area of the brain. Since the radiation is targeted, side effects are typically less severe and offer better survival rates than whole-brain therapy.

When SRS is used to treat body tumors, it is called stereotactic body radiotherapy (SBRT). This form of radiotherapy is usually reserved for people with smaller tumors that are not located too close to the center of the chest (where radiation could affect other vital organs).

Proton Therapy

Proton therapy is used in a way similar to SBRT and is administered in an attempt to eradicate the metastases. It's recommended for early-stage tumors or tumors that cannot be surgically removed because of where they're located.

Surgery

Surgery may be an option for brain metastasis if:

• There are fewer than three tumors.
• The growths are easily accessed.
• There are no other signs of cancer.

Surgery may involve the complete removal of a tumor or the partial removal to alleviate symptoms. Whole-brain radiation typically follows. Since small-cell tumors are more responsive to radiotherapy alone, surgery is more often used to remove NSCLC cells.

Palliative Care

If the various treatment options prove ineffective, palliative care may be used to offer relief and reduce the stress associated with a terminal diagnosis. This may include the use of pain medications, physical and occupational therapy, or complementary treatments to enhance comfort and improve the quality of life.

A Word From Verywell

Brain metastases due to lung cancer can be terrifying. But, as scary as it may be, it's important to remember that there is no set course when it comes to cancer. It can vary from person to person, and the "median" or "average" life expectancies you will read about don't necessarily apply to you as an individual.

If faced with brain metastases from lung cancer, work with your healthcare providers and loved ones to make the most informed choice based on a full and honest disclosure of information. It's often helpful to get a second opinion at one of the larger National Cancer Institute-designated cancer centers that specialize in lung cancer.

There are also active lung cancer communities you can join online or in-person for support and to get advice to help you make choices about your care.