Where Does Lung Cancer Typically Spread To?

Lung cancer originates when lung tissue cells grow and divide uncontrollably, forming tumors that hinder lung function. When these cancerous cells detach from the primary tumor and travel to other areas to form new tumors, this process is called metastasis. Metastasis signifies a more advanced stage of cancer, impacting treatment and outcomes.

How Lung Cancer Spreads

Lung cancer cells spread through distinct pathways. One route is through the bloodstream (hematogenous spread). Cells break away from the lung tumor, enter blood vessels, and circulate to distant organs. The body’s blood vessel network transports these cells.

Another pathway is through the lymphatic system (lymphatic spread). This system of vessels and nodes carries lymph fluid. Cancer cells invade lymphatic vessels and travel to regional lymph nodes, often the first sites outside the lungs. From these nodes, cells can spread further.

Primary Organs of Metastasis

Lung cancer frequently spreads to specific organs, often due to blood supply or proximity. The brain is a common site for metastasis, particularly in non-small cell lung cancer. Extensive blood flow makes it a receptive environment.

Bones are another frequent destination, especially the spine, pelvis, and upper arm. Bone marrow provides a supportive environment.

The liver is also a common site, receiving a large blood volume from the body. Constant blood flow increases the likelihood of cells forming secondary tumors.

Adrenal glands, located above the kidneys, are frequently affected. Their abundant blood supply contributes to their vulnerability.

Lung cancer can also spread to the other lung or different parts of the same lung. This occurs through direct extension or the circulatory and lymphatic systems. Existing lung tissue provides a familiar environment for new growths.

Recognizing Symptoms of Spread

When lung cancer spreads, it causes symptoms specific to the affected area. If cancer reaches the brain, individuals may experience headaches, memory problems, confusion, or personality changes. Seizures, blurred vision, or weakness in an arm or leg also indicate brain involvement.

Spread to bones often results in pain that can be constant and intensify with movement. This bone pain is often a deep ache and may lead to weakened bones susceptible to fractures. High calcium levels from bone breakdown can lead to dehydration or confusion.

Metastasis to the liver can cause discomfort or pain in the upper right abdomen. Other symptoms include nausea, poor appetite, weight loss, and a swollen abdomen. Jaundice (yellowing of skin and eyes) can also occur if liver function is impaired.

Adrenal gland metastasis often presents with no symptoms, especially if only one gland is affected. If symptoms arise, they can be non-specific, such as loss of appetite, weight loss, abdominal pain, or weakness. When cancer spreads to the other lung, symptoms include a new or worsening cough, shortness of breath, or chest pain.

Detecting Metastasis

Doctors use various methods to determine if lung cancer has spread. Imaging techniques are key tools. Computed tomography (CT) scans provide detailed images revealing tumor size, shape, location, and enlarged lymph nodes.

Magnetic resonance imaging (MRI) uses magnetic fields and radio waves to create detailed soft tissue images, useful for detecting spread to the brain or spinal cord.

Positron emission tomography (PET) scans involve injecting radioactive sugar, which accumulates in cancer cells for visualization. PET scans identify cancer spread throughout the body. Often, PET and CT scans are combined (PET/CT) for comprehensive images.

Biopsies, taking a tissue sample for microscopic examination, confirm cancer cells in suspected metastatic sites.