When cancer has spread from other sites of the body to the brain (metastasized), radiation therapy almost always plays a key role in treatment. The two main radiation treatment approaches are stereotactic radiosurgery and whole brain radiation therapy. There are specific instances where your doctor will recommend one form of treatment over another, depending on your specific condition and individual health factors.
Gamma Knife Radiosurgery Procedure
Though it sounds like a surgical procedure, Gamma Knife® is a form of stereotactic radiosurgery, which is a type of radiation therapy. It uses focused beams of radiation to deliver targeted treatment directly to the desired area, sparing healthy surrounding tissue and therefore reducing the risk of side effects.
Gamma Knife is typically performed in an outpatient setting and does not require a hospital stay. Many patients will only need a single treatment session, though this depends on each patient’s individual diagnosis.
The procedure itself involves four general steps. First, to ensure the patient does not move out of position during the treatment, a lightweight frame or custom mask is positioned on his or her head. The patient then undergoes a high resolution MRI to establish the size and location of the treatment target. Using this information, the radiation oncologist and neurosurgeon determine the specifications of the patient’s treatment, including target volume, radiation dose and number of treatments.
Once the treatment plan is finalized, the patient undergoes the actual treatment procedure. The frame/mask is positioned on the patient’s head, and secured to the treatment table. The table is moved into position, and the treatment begins. Patients may have a single treatment session or multiple treatments (up to five), depending on their unique condition.
Whole Brain Radiation Therapy
Whole brain radiation therapy is also done in an outpatient setting and does not require you to stay in the hospital. In contrast to Gamma Knife, whole brain radiation therapy delivers low doses of radiation to the entire brain over multiple sessions. While whole brain radiation has proven effective and has long been the gold standard in metastatic brain tumor treatment, the effect of radiation on otherwise healthy brain tissue may lead to long-term side effects. Your doctor will develop a precise treatment schedule for your condition, but many patients undergo whole brain radiation sessions five days a week, for two to three weeks.
Gamma Knife vs. Whole Brain Radiation Therapy
Because Gamma Knife and whole brain radiation therapy are both forms of radiation therapy, they share some commonalities. However, there are clear advantages of Gamma Knife vs. whole brain radiation therapy, making it the treatment of choice for many individuals.
Pros and Cons of Both Procedures
Both Gamma Knife and whole brain radiation therapy are noninvasive procedures that do not require an overnight hospital stay. Instead, you will only need to spend a matter of hours at the treatment center and will be released the same day. However, there is a difference in the number of treatments required.
Because Gamma Knife surgery uses many individual beams of low-dose radiation to target very specific areas in the brain, a larger dose of radiation may be delivered safely during each treatment session. This means you may only need to go in for treatment once. However, some patients will require up to five sessions, depending on the area being treated. By contrast, whole brain radiation therapy delivers a low dose of radiation therapy to the entire brain which must be delivered over multiple sessions. Most patients will need to undergo daily therapy for two to three weeks, for a total of 10-15 sessions.
A further difference between the two treatment modalities lies in the frequency and severity of side effects, discussed below.
Side Effects of Both Procedures
Any form of radiation therapy to the brain may result in side effects. The difference lies in the degree to which you might experience the side effects, which depends on the form of radiation therapy you undergo and the duration and frequency of your treatment. Potential side effects include:
- Nausea and vomiting
- Redness, swelling and hair loss at the treatment site
- Delayed swelling following treatment
Because whole brain radiation therapy delivers a radiation dose to the entire brain, including healthy tissues, most patients will experience side effects, which can be severe. However, Gamma Knife radiosurgery allows your doctor to target just the area of interest, sparing normal nearby structures. As a result, side effects tend to be milder and last only a day or two.
Recovery Time for Both Procedures
Because Gamma Knife radiosurgery is minimally invasive, there is essentially no recovery time. Following Gamma Knife radiosurgery, most patients are able to return to daily activity levels, including work, within a day. Though whole brain radiation therapy is also minimally invasive, the lengthy course of treatment and increased side effects can increase the recovery period before patients are able to resume all normal activities.
Gamma Knife Advantages
|Gamma Knife||Whole Brain Radiation|
|Treats conditions of the brain and skull base.||X||X|
|Does not require an overnight hospital stay.||X||X|
|Delivers targeted radiation only to the treatment area.||X|
|Results in fewer unwanted side effects, such as hair loss, nausea, fatigue and cognitive problems or memory deficits.||X|
|The targeted nature of the delivery allows for a higher radiation dose per treatment, resulting in fewer treatments.||X|
Gamma Knife for Specific Conditions
Though the most appropriate treatment option must be determined on an individual basis, Gamma Knife is often the treatment of choice for many conditions of the brain and skull base. Because Gamma Knife can be repeated and used in conjunction with other treatments, it may be the primary form of treatment or used in a combination approach, depending on the specific condition and individual health factors.
Whole Brain Radiation Therapy & Brain Metastases
The treatment the doctor recommends will depend on the patient’s individual condition. Traditionally, whole brain radiation has been prescribed as the standard of care for patients who have multiple brain metastases. These are cancers which have spread from other sites in the body and they are often very small and can be numerous. This can sometimes make these tumors difficult to target individually, so whole brain radiation therapy may be a preferred option in these cases because it can treat all of the tumors at once by treating the entire brain. Whole brain radiation therapy may cause hair loss and other short term side effects such as skin irritation, headaches and nausea. Some potential long term risks of whole brain radiation include cognitive problems or memory and/or speech deficits that do not resolve, intense headaches, seizures, and neurological deficits.
Gamma Knife for Brain Tumors
The Gamma Knife radiosurgery procedure can be used to treat many brain tumors, including acoustic neuromas, brain metastases and pituitary tumors. Gamma Knife requires fewer treatment sessions than conventional radiation therapy and spares more healthy surrounding tissues. For larger tumors, it can also be combined with surgical resection for maximal safety and effectiveness.
The Leksell Gamma Knife® Icon™ system introduces important innovations when compared to the original Perfexion system, including the ability to perform radiosurgery with the original rigid frame as well as the option to create a custom mask for patient immobilization. The Icon system also integrates 3-D imaging and software, allowing for continuous monitoring during treatment, providing the doctors with real-time information and control.
Leksell Gamma Knife® Icon™ at The Valley Hospital
The Valley Hospital is a leader in both healthcare technology and individualized patient care and is one of the first hospitals in the United States to offer the Leksell Gamma Knife Icon. The experts at The Valley Gamma Knife Center appreciate that there is no “one size fits all” approach to patient care, using the latest technology available and customizing each treatment plan to the individual patient.