Lung cancer is the most common type of cancer to spread to the brain, with at least 40% of people with lung cancer developing brain metastases at some point during their disease. What are the symptoms, what is the treatment, and what is the prognosis for lung cancer that has spread to the brain?
Definition of Lung Cancer Spread to the BrainFirst of all, it is important to define lung cancer that has spread to the brain. When lung cancer spreads to the brain it is termed "lung cancer metastatic to the brain." The term "brain cancer" in contrast, refers to cancer that begins in the tissues of the brain. Most cancers found in the brain are not brain cancers per se –- that is, they don’t start in the brain itself. Lung cancer spreads to the brain when cancer cells break off from the tumor in the lung, and spread through the bloodstream or lymphatic system into the brain and begin to grow.
What Type of Lung Cancers Spread to the Brain?Both small cell lung cancer and non-small cell lung cancer commonly spread (metastasize) to the brain. Small cell lung cancer can spread to the brain rapidly, often before the diagnosis of lung cancer is made. When small cell lung cancer has spread to the brain it is classified as extensive stage small cell lung cancer.
Non-small cell lung cancer can spread to the brain as well, though often later in the disease. When non-small cell lung cancer has spread to the brain it is classified as stage 4 (metastatic) non-small cell lung cancer.
Symptoms of Lung Cancer That Has Spread to the BrainLung cancer that has spread to the brain can cause symptoms both by destroying brain tissue, and by creating inflammation and swelling that place pressure on structures in the brain. The symptoms of lung cancer spread to the brain can vary, depending upon the part of the brain that is affected, how many tumors are present in the brain, and general health status. About a third of people have no symptoms when they have brain metastases. Some of the symptoms that suggest lung cancer may have spread to the brain include:
- Loss of balance
- Nausea and vomiting
- Difficulty walking
- Loss of coordination
- Speech problems
- Vision changes, such as loss of vision or double vision
- Weakness on one side of the body
- Memory loss
- Personality changes
Diagnosis of Lung Cancer Spread to the BrainIf your doctor suspects that your lung cancer has spread to your brain, she may order a CT scan or an MRI of your head. In many cases, an MRI is more accurate in looking for brain metastases, but may not be possible if devices (such as pacemakers) are present in your body that could interfere with the magnetic field.
PET scans, a type of radiological study that looks for actively growing cancer cells, may be done to decide if a suspicious area in the brain is due to cancer or scar tissue. Sometimes a biopsy is done to look at the cells present in the brain, especially if it is uncertain where the cancer began.
Next: Treatment options and prognosis