What is Brain Metastasis?
Brain metastases, which are a type of cancer that spreads to the brain, are a common problem and the most frequently seen type of brain tumor. It’s estimated that between 10% to 26% of patients who pass away from cancer will have this type of brain tumor. Although only a few types of cancer that spread to the brain can be fully cured with traditional therapies, there’s a chance for patients to live longer and relieve symptoms with minimal side effects. It’s becoming more common to consider patients’ cognitive abilities and quality of life as important factors as life expectancy after diagnosis continues to improve.
What Causes Brain Metastasis?
Primary cancers, including types like those in the lung, breast, and skin (melanoma), are most prone to spread to the brain. Small-cell lung cancer has a particularly high likelihood of spreading to the brain, so much so that preventive treatments like cranial irradiation (radiation therapy to the head) are the standard treatment to try to prevent this spread. Other types of cancers, like prostate or head and neck cancers, rarely spread to the brain. It can be hard to determine which patients will develop brain metastases, but the type and subtype of cancer can give doctors an indication.
Risk Factors and Frequency for Brain Metastasis
Brain metastases, which are tumors that spread to the brain from other parts of the body, are the most common type of brain tumor. It’s estimated that 98,000 to 170,000 new cases occur every year in the United States. The chances of developing brain metastases are on the rise due to a few key factors.
- Patients who have metastatic disease, meaning the disease has spread to multiple parts of their body, are living longer thanks to new treatments. These treatments include things like immunotherapy, which boosts the body’s own immune system to fight cancer.
- Also, improved detection methods like sensitive MRI techniques are being used more often. This means that even small brain metastases that are not causing symptoms can be spotted more easily.
Signs and Symptoms of Brain Metastasis
When examining a patient, it’s key to consider their symptoms, how long they’ve been experiencing them, and to what degree. You should ask if they have any specific symptoms like headaches, blurred vision, or nausea. A full neurological check-up is necessary, testing their muscle strength, senses, cooperation, reflexes, balance, recognition of touch and position, functions of the brain, speech, vision, and memory. An eye exam should also be done to check for eye swelling (papilledema). By examining the patient’s age, mental and physical performance, and overall cancer state, healthcare providers can better understand the progress of the disease and plan for future treatments.
- Consider symptoms, their duration, and intensity
- Ask about headaches, blurry vision, and nausea
- Complete a neurological exam: evaluate strength, sensation, coordination, reflexes, balance, proprioception, brain function, speech, thought, vision, and memory
- Conduct an ophthalmic examination to check for papilledema
- Record details like age, performance status, and systemic cancer burden to guide subsequent treatments
Testing for Brain Metastasis
A head CT scan or a brain MRI (Magnetic Resonance Imaging) with contrast are used to quickly examine any suspected brain tumors. MRI is typically considered the best method to do so as it can show the number, location and the surrounding swelling of any tumors present.
The health of your overall body is also important, which is why your doctor may ask for blood tests. These could include a complete blood count test, metabolic panel and liver function test.
Treatment Options for Brain Metastasis
Once a patient has been diagnosed with brain metastases, which means cancer has spread to the brain, one of the first treatments usually involves managing the swelling that typically occurs in the brain. Often, steroids are used for this, whether in pill form or given through a vein. This reduces the swelling rapidly but may need to be adjusted over time to avoid side effects from long-term high-dose steroid use.
Once the swelling is under control, more definitive treatments can be started. Options may include surgery to remove the cancer from the brain, radiotherapy that targets the entire brain, and a precise type of radiotherapy called stereotactic radiosurgery that targets only the area where the cancer is. Each type of treatment has its own pros and cons, and the specialists involved, including a neurosurgeon, a radiation oncologist, and a neuro-oncologist, will work together with the patient to decide the best course of action.
In the past, if the patient was strong enough for surgery, the recommendation was to remove the brain metastases. However, after surgeries, local recurrences can occur. To improve local control and reduce the chance of the cancer returning, patients may undergo post-operative radiations. The type of post-operative radiation depends on various factors like the number of non-operated metastases, type of tumor, patient follow-ups, and patient’s preference.
However, not all patients are typically eligible for or might choose not to go for surgery. In those cases, stereotactic radiosurgery has been found to be a viable option for controlling a small number of metastases in the brain. It tends to be effective for tumors less than one centimeter and can be used on its own without the need for whole-brain radiation first. For larger tumors, this treatment may be given over several sessions.
For patients who have many brain metastases or who are in poor health, the treatment of choice has traditionally been whole-brain radiotherapy. Although this can control brain metastases and minimizes the chance of new areas of cancer in the brain, it is associated with neurocognitive side effects to varying degrees. For some patients with extremely poor health, recent findings suggest that this treatment may offer minimal benefit over merely controlling symptoms with steroids. Therefore, each patient’s treatment will be decided on a case-by-case basis, taking their particular circumstances and the benefits and risks of the treatment into account.
What else can Brain Metastasis be?
When trying to identify brain metastases, doctors have to rule out a number of other conditions that can display similar symptoms. These might include:
- Abscess (an infected area filled with pus)
- Demyelination (damage to the protective covering of nerve cells)
- Parasitic infestation (presence of parasites in the body)
- Primary brain tumors, like glioma or ependymoma
What to expect with Brain Metastasis
The predicted outcome of cancer spreading to the brain (cerebral metastasis) depends on several different factors. These factors include:
* The age of the patient.
* The number and size of the areas where the cancer has spread to.
* The location of the original tumor.
* The other places in the body where the cancer has spread to.
* Whether there is a mass effect, which is swelling caused by the tumor pressing on surrounding tissues.
* How sensitive the tumor is to treatments like radiation therapy (radiosensitivity) and chemotherapy (chemosensitivity).
Possible Complications When Diagnosed with Brain Metastasis
Potential Complications Include:
- Pressure on surrounding brain tissue
- The brain shifting out of its normal position
- Seizures
- Build-up of fluid in the brain
- Spread of disease to adjacent brain tissue
- Neurological problems
- Death
Preventing Brain Metastasis
The doctor will speak with the patient about what their diagnosis means and what they can expect in terms of recovery or long-term effects. It’s crucial for the patient to follow the treatment plan and take their medications as prescribed, as this will help them get better or manage their condition effectively.
