Brain metastasis means that a cancer that develops in tissues and organs outside the brain spreads to the brain tissue and forms a tumor there. This type of tumor is also called secondary tumor. The most common tumors in the brain are these types of tumors. It is one of the leading causes of death in cancer patients.
Cancer cells usually come to the brain through blood. After reaching the brain, these cells can cause one or more tumors. Cells that break away from the tumor in any part of the body enter the blood or lymphatic system. The first place they go from here is the lungs, and then they can go to other organs. The immune system tries to destroy these mobile cancer cells, but if the number of cancer cells is too large, the immune system cannot destroy them all at once.
Because 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 fast that brain metastasis can be diagnosed before the diagnosis of lung cancer.
Some primary organ cancers have a tendency to metastasize to a number of major organs. For example, colon cancer tends to metastasize to the liver and lungs. Breast cancer metastasizes to the bone, lungs, and brain. These trends are thought to be due to a number of hormones or proteins.
Although all types of cancer in the body can metastasize to the brain, most often lung, breast, kidney and colon cancers and melanoma metastasize to the brain. Breast and kidney cancers often cause a single tumor in the brain. Lung and colon cancer and melanoma cause a large number of tumors. Approximately 60% of all brain metastases originate from lung cancer. About 20-30% of all breast cancers also metastasize to the brain. In approximately 15% of metastatic brain tumors, the location of the primary tumor is undetectable. In this case, it is probably destroyed by the body’s immune mechanism after the first (primary) cancer has formed and given metastasized cells to the blood. But metastasis cells can reach the brain and continue to multiply.
What are the characteristics of cancers that most often metastasize to the brain?
Lung cancer:
1. cancers that most often metastasize to the brain
2. about 35% of lung cancers metastasize to the brain
3. brain metastasis can occur before or at the same time as primary lung cancer
4. multiple metastases are common in the brain
Breast cancer:
1. the second most common are cancers that metastasize to the brain
2. about 10-30% of breast cancers metastasize to the brain
3. metastases occur several years after breast cancer is diagnosed
4. brain metastasis usually occurs in younger and pre-menopausal women
5. single or multiple metastatic tumors are equally common
Melanomas
1. the third most common are cancers that metastasize to the brain
2. approximately 30-40% of melanomas metastasize to the brain or meninges
3. metastases occur several years after a primary tumor is diagnosed
4. multiple brain metastases are common
5. metastatic tumors tend to bleed because they are rich in blood vessels
Kidney cancer
1. the fourth most common are cancers that metastasize to the brain
2. about 5-10% of kidney cancers have brain metastases
3. metastases occur several years after a primary tumor is diagnosed
4. metastases are usually single tumors
5. metastatic tumor usually also has blood vessels
Colon cancer
1. the fifth most common are cancers that metastasize to the brain
2. about 5% of colon cancers metastasize to the brain
3. metastases occur several years after a primary tumor is diagnosed
4. metastases are usually single tumors
The incidence of cancer increases with age. As more successful results are obtained in the treatment of cancers and people begin to live longer, metastatic cancers have also begun to be seen more. Metastatic cancers are most common in people over the age of 65. It is usually more common in men than in women.
Signs and symptoms of a brain tumor occur depending on the location of the tumor in the brain.
The most common signs and symptoms are headache, weakness, imbalance, and seizures.
In addition to those that occur in the actual cancer in the body, the following signs and symptoms can be observed in brain metastases.
• Increased intracranial pressure. In most patients, the findings occur due to increasing mass in the head, increasing pressure in the head. Indicators of increased intracranial pressure are headache, vomiting, and disorders of consciousness.
• Headache. The first symptom that occurs in about half of patients with a brain tumor is a headache. Most patients have headaches.
• Vomiting. Vomiting is often accompanied by headaches. It occurs in children rather than adults. This vomiting in children is so severe that it is called “gushing” – style vomiting.
• Disorders of consciousness. Patients with a brain tumor, experience disorders of consciousness during a period of their illness. This condition can range from a mild personality disorder to irreversible coma.
• Convulsion About 35% of brain tumor patients experience epilepsy-like convulsions. In this case, contractions and loss of consciousness occur throughout the body. This condition occurs more often in brain tumor patients over the age of 45.
• Focal neurological findings. Although headaches, disorders of consciousness, and convulsions can occur in tumors in many parts of the brain, some findings are characteristic of where the tumor holds in the brain. Accordingly, signs of tingling, loss of sensation or decreased strength may occur on the opposite side of the body, depending on where the tumor is located.
After a comprehensive neurological examination, CT or MRI can identify masses sapping space in the brain. During CT and MRI, an intravenous drug may be required to better view the tumor. With these examinations, information about the tumor’s location, size, number and possible type of can be obtained. However, the definitive diagnosis can only be made by examining a piece taken under a microscope. A piece of the tumor can be removed during surgery or during a biopsy. A biopsy is the name given to the process of removing a piece of the tumor to make a diagnosis. This part is then examined by a pathologist under a microscope. If brain metastasis is diagnosed before the cancer is found, the necessary tests are performed to find the location of the actual cancer.
The treatment depends on the type and size of the tumor, how many metastatic tumors there are, where the actual tumor is, how the person responds to the treatment of the actual tumor, and the overall health of the person. The aim of treatment is to eliminate signs and symptoms, relieve intracranial pressure, prevent seizures, maintain daily life in a more comfortable way and improve the quality of life.
• Supportive treatment. A number of medications can be used to relieve headache or pain in general, prevent transfers, and eliminate tissue swelling (edema) that may develop due to the tumor. These drugs are painkillers, phenytoin and steroids.
• Chemotherapy is not often used to treat metastatic brain tumors. But some research in recent years has shown that some tumors are sensitive to chemotherapy. These tumors include small cell lung cancer, breast cancer, germinal cell tumors, and lymphoma. Chemotherapy can also be tried in a number of tumors that metastasize to the membranes of the brain and spinal cord. The size and number of tumors, the type, the condition of the primary cancer, what drugs are available in that country, and the responses to previous chemotherapy are important when making decisions about chemotherapy. In some cases, drugs used for the first tumor do not work for brain metastases. The reason for this is unknown. In this case, different drugs can be used than chemotherapy drugs used in primary cancer.
• Surgical treatment is the preferred treatment for some brain metastases. During surgery, both parts of the tumor are taken for definitive diagnosis and the tumor is removed. According to other treatment methods, surgical treatment is performed if it is thought that it will both improve the quality of life and prolong life.
• Radiation therapy. This treatment is used to treat single or multiple metastatic tumors. It is also used to prevent metastases before brain metastases develop in newly diagnosed small cell lung cancers and acute lymphoblastic leukemia. Another form of use is to eliminate the signs and symptoms caused by a brain tumor. in his approach, he tries to destroy the tumor cells by giving radiation to the tumor.
Radiation therapy can be given to the entire brain in divided doses. Another option is to send a high dose of radiation beam to the tumor at a time using gamma knife or linear accelerator. The advantage of this technique is that it can also be used in tumors that cannot be operated on. Because the brain does not open, it also has less risk than surgery. In addition, the duration of hospitalization is also shorter.
After the treatment of the brain tumor is completed, the patient is monitored by MRI or CT every three months for a year. This monitoring is done to determine whether the tumor has recurred. Like other tumors anywhere in the body, metastatic brain tumors can recur. Treatment of recurrent brain tumors begins with the evaluation of the primary tumor. If the primary tumor is under control, surgery, radiosurgery, radiation therapy, or in some cases full brain irradiation can be performed again to treat the metastatic tumor. Chemotherapy or immunotherapy are also among the options.
