July was a tough month and I haven't posted because I just did not want to post bad news. I started this blog to help others in the same situation as Roxy and I, so here I am. I am also posting the MRI report below.
There seems to be a late effect side effect that has injured a part of her brain that was healthy in the previous MRI.
I have since found this article that talks about late effects of Cyberknife that can occur months after the treatment, it states these late effects are rare, but Roxy has a few: brain changes and and a mass in her spleen. She is also having gallblader and liver changes, but that may be due to the steroids she has been on. I have also found another dog, Farrah, who had Cyberknife and developed another cancer as well. While Cyberknife gave Roxy 4 fabulous months that she would not have had, it is not an easy transition going through the brain changes. She fails the knuckle test on 3 of her 4 paws. Her brain has almost no knowledge of her left rear leg, her left front leg is getting pretty bad, and now the right rear seems to be having problems. Having a 65 lb dog with neurological issues is physically demanding, although my body can now fully lift her when necessary. She cannot balance herself to urinate, and needs support on her left side or she will fall down. Most days I can still entice her to walk some with Plato Duck Treats, but some days her legs just wont work. When this happens she either falls to the side or drops down onto her belly. I have a fabulous wagon to take her out in, and there is a lot of love from people that we meet. It also seems that her tongue doesn't always work properly.
So how do I feel about Cyberknife? From what I can tell from the blogs of others, dogs seem to have these late effects pretty frequently. I believed in the science that we could shrink the tumor with little damage to surrounding tissue. I figured that with the brain tumor gone Roxy would likely have other health issues, but I never imagined that there would be brain changes that were not there before that would cause a new set of problems for Roxy. Cyberknife was Feb 24, so we are a little over 5 months out. I believe the Cyberknife caused these brain changes. Immediately after the Cyberknife was when Roxy first started dragging one of her toes on her rear left leg. This was a new symptom that was not present previously.
I also found a couple of stories of dogs who chose the Dr. Pluhar' canine brain tumor clinical trials. Riley seems to be doing great years later, Jake only made it two months.
I guess we never know what we are going to get, I have left the heartache behind and am focusing on the time we still have.
In health to you all.
Anne & Roxy
Roxy's MRI Report
Stereotactic Radiosurgery (SRS) and Stereotactic Body Radiotherapy (SBRT)
What is stereotactic radiosurgery and how is it used?Stereotactic radiosurgery (SRS) is a highly precise form of radiation therapy initially developed to treat small brain tumors and functional abnormalities of the brain. The principles of cranial SRS, namely high precision radiation where delivery is accurate to within one to two millimeters, are now being applied to the treatment of body tumors with a procedure known as stereotactic body radiotherapy (SBRT).
Despite its name, SRS is a non-surgical procedure that delivers precisely-targeted radiation at much higher doses, in only a single or few treatments, as compared to traditional radiation therapy. This treatment is only possible due to the development of highly advanced radiation technologies that permit maximum dose delivery within the target while minimizing dose to the surrounding healthy tissue. The goal is to deliver doses that will destroy the tumor and achieve permanent local control.
SRS and SBRT rely on several technologies:
- three-dimensional imaging and localization techniques that determine the exact coordinates of the target within the body
- systems to immobilize and carefully position the patient and maintain the patient position during therapy
- highly focused gamma-ray or x-ray beams that converge on a tumor or abnormality
- image-guided radiation therapy (IGRT) which uses medical imaging to confirm the location of a tumor immediately before, and in some cases, during the delivery of radiation. IGRT improves the precision and accuracy of the treatment
Although SRS commonly refers to a one-day treatment, physicians sometimes recommend multiple stereotactic delivered treatments. This is important for tumors larger than one inch in diameter as the surrounding normal tissue exposed to the single high dose of radiation must be respected and limited, and the volume of normal tissue treated increases proportionally to the tumor size. Delivering the radiation in a few sessions as opposed to one, can improve safety and allow the normal tissue to heal in between treatments. Therefore, fractionating the treatment allows for high doses to still be delivered within the target, while maintaining an acceptable safety profile. This procedure is usually referred to as fractionated stereotactic radiotherapy (SRT), and typically refers to the delivery of two to five treatments of focused radiation.
SRS and SBRT are important alternatives to invasive surgery, especially for patients who are unable to undergo surgery and for tumors and abnormalities that are:
- hard to reach
- located close to vital organs/anatomic regions
- subject to movement within the body
- many types of brain tumors including:
- benign and malignant
- primary and metastatic
- single and multiple
- residual tumor cells following surgery
- intracranial, orbital and base-of-skull tumors
- arteriovenous malformations (AVMs), a tangle of expanded blood vessels that disrupts normal blood flow in the brain and sometimes bleeds.
- other neurological conditions like trigeminal neuralgia (a nerve disorder in the face), tremor, etc.
- head and neck
What equipment is used?There are three basic kinds of equipment, each of which uses different instruments and sources of radiation:
- The Gamma Knife®, which uses 192 or 201 beams of highly focused gamma rays all aiming at the target region. The Gamma Knife is ideal for treating small to medium size intracranial lesions. See the Gamma Knife page for more information.
- Linear accelerator (LINAC) machines, prevalent throughout the world, deliver high-energy x-rays, also known as photons. The linear accelerator can perform SRS on larger tumors in a single session or during multiple sessions, which is called fractionated stereotactic radiotherapy. Multiple manufacturers make this type of machine, which have brand names such as Novalis Tx™, XKnife™, Axesse™ and CyberKnife®. See the Linear Accelerator page for more information.
- Proton beam or heavy-charged-particle radiosurgery is in limited use in North America, though the number of centers offering proton therapy has increased dramatically in the last several years. See the Proton Therapy page for more information.
Who will be involved in this procedure and who operates the equipment?The treatment team is comprised of a number of specialized medical professionals, typically including a radiation oncologist, medical radiation physicist, radiologist, dosimetrist, radiation therapist, and radiation therapy nurse.
- The radiation oncologist and, in some cases, a neurosurgeon head the treatment team and oversee the treatment; they outline the target(s) to be treated, decide on the appropriate radiation dose, approve the treatment plan, and interpret the results of radiosurgical procedures.
- A radiologist interprets imaging that identifies the target(s) to be treated in the brain or body.
- The medical radiation physicist ensures the delivery of the precise dose of radiation.
- The physicist, or a dosimetrist under the supervision of the physicist, uses special computer software to devise a treatment plan; he or she calculates the exposures and beam configuration to conformally treat the target(s) to the prescribed dose.
- A highly trained radiation therapist positions the patient on the treatment table and operates the machine from an adjacent protected area. The radiation therapist can observe the patient through a window or on a closed-circuit television and is able to communicate with the patient throughout the procedure. In the case of the Gamma Knife, the neurosurgeon and/or radiation oncologist may help position the patient for treatment and the radiation oncologist may operate the machine.
- The radiation therapy nurse assesses the patient, provides the patient with information about the treatment, monitors the patient during treatment, and helps answer questions after treatment.
- A neurologist or neuro-oncologist may participate with the radiation oncologist and neurosurgeon in the multidisciplinary team that considers various treatment options for individual cases and helps decide who may benefit from radiosurgery for lesions in the brain.
How is the procedure performed?
• Stereotactic Radiosurgery Using the Gamma Knife
In the first phase, a nurse will place a small needle in your hand or arm to give you medications and contrast, if needed, for imaging. A neurosurgeon will use local anesthesia to numb two spots on your forehead and two spots on the back of your head. A box-shaped head frame will be attached to your skull using specially designed pins to keep your head from moving within the frame until the treatment session is finished. This lightweight aluminum head frame is also a guiding device that makes sure the Gamma Knife beams are focused exactly where the treatment is needed.
Next, you will be taken to an imaging area where a magnetic resonance imaging (MRI) scan will be performed to show the exact location of the tumor in relation to the head frame. In some cases, a computed tomography (CT) scan may be performed instead of, or in addition to, an MRI scan. If you are having treatment for an arteriovenous malformation, you may also have an angiogram. New developments in Gamma Knife software allow for pre-planning. Therefore, you may have your treatment planning MR images prior to the day of your treatment to improve the efficiency of the treatment process.
During the next phase, you will be able to relax for an hour or two while your treatment team identifies the tumor(s) for treatment and develops a treatment plan using special computer software to optimally irradiate the tumor and minimize dose to surrounding normal tissues.
Next, you will lie down on the Gamma Knife bed and your head frame will be fixed to the machine before beginning treatment. You will be made comfortable with a pillow or wedge-shaped sponge under your knees and a blanket over you. The treatment team will then go to the control area outside the treatment room to begin your treatment. You will be able to talk to your physician through a microphone in the helmet, and a camera will allow the team to see you at all times. The bed you are lying on will move backward into the Gamma Knife machine. You will not feel the treatment and the machine is very quiet. Depending on the Gamma Knife model and the treatment plan, the whole treatment may be performed without interruption or it may be broken up into multiple smaller parts. The total treatment may last less than one hour or up to four hours. A chime will sound when the treatment is complete and the bed will return to its original position. As soon as the treatment is finished, you will sit up and the head frame will be removed. In most cases, you should be able to go home soon afterward.
• Radiosurgery Using the Linear Accelerator
When SRS is delivered using CyberKnife, a robotic arm moves the compact LINAC around the patient under image-guidance. The CyberKnife is also based on delivering SRS without an invasive head frame, and a more simple plastic head mask can be used to keep the head from moving during delivery which can improve patient comfort. The development of frameless SRS is possible due to the incorporation of image-guidance in the delivery of treatment. Now, most LINAC based SRS technology is moving towards frameless SRS. The Gamma Knife has also developed frameless technology in order to spare the patient the invasive frame placement procedure. Frameless SRS also allows for fractionated SRS, or SBRT, which again may be an advantage for large tumors or those in particularly critical locations.
For some technologies like the CyberKnife that base image-guidance according to an x-ray based solution, you may be asked to have a fiducial marker placed in or near your tumor for selected cases. However, for most CT based image-guidance technologies, this step is not needed. If a fiducial is required, depending on the location of your tumor, your radiation oncologist may work with a pulmonologist, gastroenterologist or radiologist to have one to four fiducial markers placed near the tumor. Placement of the fiducial marker is almost always an outpatient procedure.
Next, your radiation oncologist will determine the method of aligning your body with the beams from the linear accelerator, which is called a simulation. Immobilization devices are often used to align patients very precisely and make sure they remain still during simulation and treatment. Some of these systems may hold you quite tight; therefore you should tell your physician if you suffer from claustrophobia. After an immobilization device is created for you, a CT scan is performed over the area to be treated. Your physicians may also perform a '4DCT,' where the CT scan obtains information on how your tumor moves while you breathe. This is very common for tumors in the lungs or liver. After the scan is completed, you will be sent home.
The third part of the course is planning. The radiation oncologist will work with a radiation dosimetrist and medical physicist to plan the beam arrangement best suited for your tumor. They may incorporate other imaging techniques, such as MRI or PET/CT. Using specialized software, the team will go through hundreds of different combinations of beams to figure out which would be best for your situation.
Radiation delivery of SBRT is done on a linear accelerator. There are normally no restrictions on eating or drinking, though some patients may take an anti-inflammatory, anti-nausea or anti-anxiety medication prior to the treatment. You will be placed in the immobilization device. X-rays or a CT scan (depending on the mode of image-guidance specific to the LINAC technology) will be taken to line up the beams of radiation with the tumor prior to starting the radiation therapy. The radiation therapist will position you with guidance from the radiation oncologist based on these x-rays. The radiation therapist will then deliver the treatment. Sometimes, x-rays or a CT scan will be taken during the treatment to monitor the position of the tumor. Treatment can take up to one hour or more.
Is there any special preparation needed for the procedure?SRS and SBRT are usually performed on an outpatient basis. However, be prepared to spend up to a half-day or more at the facility. You will be informed whether you need to have someone accompany you and drive you home afterward.
You may be asked not to eat or drink anything after midnight on the night before your treatment. You should ask your physician about taking any medications on the day of your treatment and bring those medications with you to the procedure. You should also tell your physician if any of the following apply to you:
- You are taking medications by mouth or insulin to control diabetes.
- You are allergic to intravenous contrast material, shellfish, or iodine.
- You have a pacemaker, artificial heart valve, defibrillator, brain aneurysm clips, implanted pumps or chemotherapy ports, neurostimulators, eye or ear implants, stents, coils or filters.
- You suffer from claustrophobia.
What will I feel during and after the procedure?Radiosurgery treatments are similar to having an x-ray. In general you will not be able to see, feel or hear the x-rays. One exception is that some patients who are having treatments to the brain may see flashes of light while the machine is on, even with their eyes closed. There is no pain or discomfort from the actual treatment.
If you experience pain for other reasons, such as back pain or discomfort from the head frame or immobilization device, you should let your doctor or nurse know.
When the head frame is removed, there may be some minor bleeding from the pin sites that will be bandaged. You may experience a headache and can ask for medication to help make you feel more comfortable.
In most cases, radiosurgery and SBRT patients can resume all of their normal activities within one or two days.
Side effects of radiation treatment include problems that occur as a result of the treatment itself as well as from radiation damage to healthy cells in the treatment area.
The number and severity of side effects you experience will depend on the type of radiation and dosage you receive and the part of your body being treated. You should talk to your doctor and nurse about any side effects you experience so they can help you manage them.
Radiation therapy can cause early side effects during or immediately after treatment, and are typically gone within a few weeks. Late side effects can occur months or years later. Common early side effects of radiation therapy include tiredness or fatigue and skin problems. Skin in the treatment area may become more sensitive, red, irritated, or swollen. Other skin changes include dryness, itching, peeling and blistering.
Depending on the area being treated, other early side effects may include:
- hair loss in the treatment area
- mouth problems and difficulty swallowing
- eating and digestion problems
- nausea and vomiting
- soreness and swelling in the treatment area
- urinary and bladder changes
- brain changes
- spinal cord changes
- lung changes
- kidney changes
- colon and rectal changes
- joint changes
- mouth changes
- secondary cancer
- fracture of bones
Using techniques such as SBRT, the aim is to maximize the cancer-destroying capabilities of radiation treatment while minimizing its effect on healthy tissues to limit the side effects of the treatment itself.
Additional Information and Resources
RTAnswers.orgStereotactic Radiation Therapy
OthersAmerican Stroke Association
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