Where Does Lung Cancer Spread?

Many people with lung cancer are all too aware that lung cancer can spread. Nearly 40% of those newly diagnosed with lung cancer are already at stage 4 and have metastases, cancer that has spread to other parts of the body. Symptoms and treatments for metastatic lung cancer vary depending on where the new tumors appear, but with each form, it's important to review all of your options and to stay hopeful as you try to manage your condition.

How Lung Cancer Spreads

Lung cancer spreads when cells break off from a tumor and travel through the bloodstream or the lymphatics (vessels in the body through which lymph and white blood cells travel) to distant regions of the body and grow. This process is called metastasis.

Lung cancer in both its forms—non-small cell lung cancer (NSCLC) or small cell lung cancer (SCLC)—can spread to nearly any region of the body.

The most common areas for lung cancer to spread are the:

• Lymph nodes
• Liver
• Bones
• Brain
• Adrenal glands

Lymph Nodes

Most lung cancers first spread to lymph nodes within the lung or around the major airways. This occurs during stage 2B of NSCLC or the limited stage of SCLC. Cancer cells can then travel to areas in the chest further from the initial tumor and on to other regions of the body.

As long as the cancer only spreads as far as nearby lymph nodes, it isn't considered metastatic (stage 4 non-small cell or extensive-stage small cell lung cancer).

Often, people will have no symptoms when lung cancer spreads to nearby lymph nodes. When NSCLC and SCLC extend to lymph nodes beyond the lungs, you may notice a lump in your neck or your armpit, similar to (but usually firmer than) the swollen glands experienced with a sore throat.

Surgery has proven to be the most effective treatment for early-stage NSCLC, requiring either partial or complete removal of lymph nodes.

Adjuvant therapies—radiation, chemotherapy, and targeted therapy—may be used with surgery to help reduce the risk that the cancer will resurface.

Bone

Among the difficult complications associated with NSCLC is lung cancer metastatic to bone. Roughly 30% to 40% of people with advanced lung cancer will develop bone metastases. The areas that are affected include:

• Spine: The bones where lung cancer is most likely to spread, especially the vertebrae in the chest and lower abdominal area
• Pelvis: An especially difficult area to treat with a high rate of recurrence (almost 40%)
• Humerus and femur: These are the upper bones of the arms and legs
• Hands and feet: Lung cancer is unusual in that it can spread to these areas

The most common symptom of bone metastases is pain. Often the pain begins gradually, feeling like a muscle pull or strain, and progresses to more severe pain. Due to the weakening of the bone from the tumor, some people develop fractures (pathological fractures) that occur with minimal trauma or even during normal daily activities.

If lung cancer spreads to the spine, it may put pressure on the spinal cord (spinal cord compression) which can be a medical emergency. This may cause weakness or tingling in your legs or difficulty walking.

Cancers that metastasize to bone may also break down bone releasing calcium into the blood (hypercalcemia), causing symptoms of confusion, muscle weakness, and loss of appetite among others.

Tests to look for bone metastases may include a bone scan, positron emission tomography (PET), computed tomography (CT), or magnetic resonance imaging (MRI).

The primary goal in treatment of bone metastases is to reduce pain and to repair or prevent fractures. Options include pain medications, radiation therapy, medications to try to prevent the breakdown of bone, and surgery to stabilize bones.

Brain

Lung cancer is the most common cancer that spreads to the brain; as many as 40% of people diagnosed with lung cancer will develop brain metastases at some point. Both non-small cell lung cancer and small cell lung cancer can be involved.

SCLC can spread to the brain rapidly, often before a first cancer diagnosis is even made. Prophylactic cranial irradiation (PCI), a type of radiation therapy, may be used to attempt to prevent this from occurring.

Lung cancer that has spread to the brain can cause symptoms both by destroying brain tissue and by creating inflammation and swelling that places pressure on structures in the brain.

In cases where symptoms do occur, signs may include:

• Headaches
• Nausea and vomiting
• Seizures
• Loss of balance and coordination
• Difficulty with speaking
• Vision changes
• Weakness on one side of the body
• Fatigue

Lung cancer metastatic to the brain is usually diagnosed with either a CT scan or an MRI of the brain.

Treatment is primarily palliative, meaning that the goal is to control symptoms and not to try to cure the cancer. Steroids may be used to decrease swelling. Pain medications and anti-seizure medications may be used to control headaches and seizures. Radiation therapy may also be very effective in reducing symptoms for some people.

Sometimes only one or a few brain metastases are present—what's called oligometastases. In these instances, treatment with either surgery or stereotactic body radiotherapy (SBRT), cyber knife or gamma knife, has helped some people gain long-term control over the disease.

Liver

Lung cancer that has spread to the liver may not cause any symptoms and is often discovered when a test, such as a CT scan, is done to look for spread of your cancer. When symptoms are present, they may include:

• Loss of appetite
• Weight loss
• Fatigue
• Bloating and leg swelling (edema)
• Itching
• Jaundice, yellowing of the skin or whites of the eyes

Tests that are done to check whether lung cancer has metastasized to the liver may include an abdominal ultrasound, a CT scan of your abdomen, or a PET scan.

Chemotherapy is usually recommended to treat the cancer cells in the liver as well as the primary cancer. In rare cases, if only a single tumor or a few tumors are present, surgery may be recommended to remove the tumors. Sometimes a procedure called embolization may be recommended as well.

Adrenal Glands

Adrenal glands are small glands that sit on top of the kidneys and produce hormones. Lung cancer that spreads to these glands does not usually cause any symptoms and is most often discovered incidentally when a scan is done to stage cancer.

Treatment with chemotherapy may be helpful. In a very small number of people who are both able to have their lung cancer removed and only have one spot in one of the adrenal glands, surgery to remove the adrenal gland and adrenal metastases has resulted in long-term survival.

Other Areas

While the regions above are the most common sites for lung cancer metastases, lung cancer has on occasion spread to the stomach, small and large intestines, the pancreas, the eye, the skin, the kidney, and even the breast.

Prognosis

Other than metastases in the lymph nodes, which happens during early stages of the disease, lung cancer that has spread to distant regions has a very poor statistical prognosis.

That said, there are people who have survived and done well for many years even after a diagnosis of lung cancer that has spread. 

A Word From Verywell

Newer treatments, such as immunotherapy drugs, offer hope that, for some people, long-term lung cancer survival may be possible. While these drugs do not work for everyone, some people with advanced disease have had excellent results. Be sure that you speak to your doctor about all of your options if you are diagnosed with metastatic lung cancer.