A brain metastasis is a brain tumor that develops from cancer cells that spread from another cancerous tumor in the body, usually through the bloodstream. Brain metastases occur in about 20 percent to 40 percent of cancer patients. Up to 75 percent of patients have multiple lesions.
The most common sources of brain metastases in adults include lung, breast, and skin cancers. Doctors are unable to locate the origins of metastases in about 15 percent of patients. Almost any systemic cancer is capable of spreading to the brain. Identifying the source of a brain metastasis is often critical for choosing the most effective treatment.
What are the symptoms of brain metastases?
About two-thirds of brain metastases produce symptoms at some point. Symptoms are caused by increased pressure in the skull, brain tissue destroyed by the tumor or both. Metastatic tumors frequently lead to a swelling, in which fluid accumulates within brain tissues and can damage brain functions.
Increased intracranial pressure can produce nonspecific symptoms like:
Destroyed brain tissue, known as focal irritation, can lead to seizures, paralysis, impaired vision, epileptic seizures and a variety of neurological impairments, depending on the tumor location.
What are the treatment options?
Treatment options usually depend on, among other things, the tumor location and type, the patient’s age and general health, and the status of the cancer in other parts of the body.
Oral steroid medication
Oral steroids help reduce swelling and the associated symptoms. While effective in the short term, oral steroids are rarely effective for long-term treatment of brain metastases. Larger doses are needed over time to maintain the steroids’ effectiveness. As the dosage increases, debilitating side effects tend to increase as well.
Open surgery can benefit patients with a single metastatic brain tumor that can be safely accessed and who don’t have cancer elsewhere in the body. In these cases, aggressive surgical tumor removal often has better outcomes compared to radiation therapy. Surgery also provides tissue for doctors to confirm a metastasis diagnosis or determine the tumor’s origin. The risks of surgery vary depending on the patient’s health and the tumor location.
Whole-brain radiation therapy
Radiation therapy, often referred to as whole-brain radiation therapy, is a common form of treatment for the vast majority of patients with brain metastases. Patients undergo daily radiation treatments over the course of several weeks. Whole-brain radiation therapy can significantly shrink many brain metastases and, in doing so, relieve the associated symptoms.
Whole-brain radiation therapy often doesn’t completely eliminate tumors, however, and regrowth is common. There also can be side effects that affect brain function and become more severe over time, although injury from radiation may be alleviated by spreading treatment over longer periods of time.
In some cases, whole-brain radiation therapy may be used in combination with stereotactic radiosurgery. However, many medical experts debate whether radiosurgery is best used alone or with conventional radiation. The risks and benefits of each method should be discussed thoroughly with your doctor.
Radiosurgery with the Gamma Knife delivers high-dose radiation while minimizing exposure to healthy tissue by precisely aiming multiple beams from different angles. Therefore, radiosurgery is the most aggressive radiation treatment available for brain metastases. While whole-brain radiation therapy can require numerous treatments over several weeks, radiosurgery is completed in a single session. Radiosurgery can be used alone or combined with surgery or whole-brain radiation therapy, depending on specific clinical circumstances.
Radiosurgery is a widely accepted treatment for a single metastatic brain tumor that cannot be safely removed surgically. Radiosurgery also is used frequently for patients with multiple metastatic tumors, a condition that usually prevents surgery. Medical studies have shown that radiosurgery may be as effective as conventional surgery, regardless of whether the tumor can be safely removed by surgery. Radiosurgery also can be used with surgery to eliminate another inoperable tumor or to treat a tumor that persists or regrows after surgery.
Recovery time with radiosurgery is much shorter than standard surgery. Radiosurgery doesn’t require anesthesia and is an important alternative to surgery when patients are not in good health otherwise. Treating more than one metastasis also is much easier with radiosurgery than conventional surgery.