Frequently Asked Questions About Brain Metastasis
What Is Brain Metastasis?
Brain metastasis means that a cancer developing in tissues and organs outside the brain spreads to the brain tissue and forms a tumor there as well.
How Does Brain Metastasis Occur?
Cancer cells usually reach the brain through the bloodstream. After reaching the brain, these cells can cause one or more tumors. Cells that break away from a tumor anywhere in the body enter the blood or lymphatic system. The first place they reach from there is the lungs, and then they may spread to other organs as well.
The immune system tries to destroy these mobile cancer cells, but if the number of cancer cells is too high, the immune system cannot eliminate all of them at once. Since the blood flow of the lungs goes directly to the brain, lung cancer can metastasize to the brain very quickly. Sometimes this metastasis occurs so rapidly that brain metastasis may be diagnosed before lung cancer is diagnosed. Some primary organ cancers have a tendency to metastasize to certain specific organs.
For example, colon cancer tends to metastasize to the liver and lungs. Breast cancer metastasizes to the bones, lungs, and brain.
In Whom / In Which Cancers Is Brain Metastasis Most Common?
Although any type of cancer in the body can metastasize to the brain, it most commonly occurs with lung, breast, kidney, and colon cancers, as well as melanoma. Breast and kidney cancers generally cause a single tumor in the brain. Lung and colon cancer, as well as melanoma, tend to cause multiple tumors. Approximately 60% of all brain metastases originate from lung cancer. Approximately 20-30% of all breast cancers metastasize to the brain.
In approximately % of metastatic brain tumors, the location of the primary tumor cannot be identified. In this case, the initial (primary) cancer was probably destroyed by the body’s immune mechanisms after forming and releasing metastatic cells into the bloodstream. However, metastatic cells may still reach the brain and continue to grow.
What Are the Characteristics of the Cancers That Most Commonly Cause Brain Metastasis?
Lung Cancers
These are the cancers that most commonly cause brain metastasis. Approximately 35% of lung cancers metastasize to the brain. Brain metastasis may appear before or at the same time as the primary lung cancer. Multiple metastases in the brain are common.
Breast Cancers
These are the second most common cancers that cause brain metastasis. Approximately -30% of breast cancers metastasize to the brain. Metastases appear several years after the diagnosis of breast cancer. Brain metastasis generally occurs in younger, premenopausal women. Single or multiple metastatic tumors are seen with equal frequency.
Melanomas
These are the third most common cancers that cause brain metastasis. Approximately 30-40% of melanomas metastasize to the brain or meninges. Metastases appear several years after the diagnosis of the primary tumor. Multiple brain metastases are common. Since metastatic tumors are rich in blood vessels, they tend to bleed.
Kidney Cancers
These are the fourth most common cancers that cause brain metastasis. Approximately 5-10% of kidney cancers metastasize to the brain. Metastases appear several years after the diagnosis of the primary tumor. Metastases are generally single tumors. Blood vessels are also usually present in the metastatic tumor.
What Are the Most Common Signs / Symptoms Seen in Brain Metastases?
The signs and symptoms of a brain tumor appear depending on the location of the tumor within the brain. The most common signs and symptoms are headache, weakness, imbalance, and seizures. In addition to the findings caused by the main cancer elsewhere in the body, the following signs and symptoms may also be seen in brain metastases.
Increased intracranial pressure. In most patients, the findings occur due to the growing mass inside the skull increasing intracranial pressure. Indicators of increased intracranial pressure include headache, vomiting, and disturbances of consciousness. Headache. The first symptom seen in approximately half of patients with a brain tumor is headache. Most patients experience headache. Vomiting. Vomiting usually accompanies headache. It is seen more often in children than in adults.
In children, this vomiting can be so severe that it is called “projectile” vomiting. Disturbances of consciousness. Patients with brain tumors may experience disturbances of consciousness at some stage of their illness. This may range from a mild personality change to irreversible coma. Seizures. Approximately 35% of brain tumor patients experience epilepsy-like seizures. In this case, there are convulsions throughout the body and loss of consciousness. This is more common in brain tumor patients over the age of 45.
Focal neurological findings. Although headache, disturbances of consciousness, and seizures may occur in tumors in many areas of the brain, some findings vary depending on the location of the tumor in the brain. Accordingly, depending on where the tumor is located, there may be tingling, sensory loss, or weakness on the opposite side of the body.
Is It Possible for Brain Metastases to Recur After Treatment?
After the treatment of the brain tumor is completed, the patient is monitored with MRI every three months for one year. This follow-up is done to determine whether the tumor has recurred. Like other tumors anywhere in the body, metastatic brain tumors can also recur. Treatment of recurrent brain tumors begins with evaluation of the primary tumor.
If the primary tumor is under control, treatment options for the metastatic tumor may include repeat surgery, radiosurgery, radiation therapy, or in some cases whole-brain irradiation. Chemotherapy or immunotherapy may also be among the options.
