excerpts from VHL Handbook
In VHL, blood vessel-rich tumors form in the brain and spinal cord, called hemangioblastomas. The most common location of these tumors in the brain is the cerebellum, and in the spine is the cervical spine. When hemangioblastomas occur, they are generally not treated until symptoms begin to develop, or if they are growing rapidly and loss of function is expected. With regular visits to a neurosurgeon on the schedule recommended by your medical team, early signs may be found that may require further testing, usually with MRI. Early signs and symptoms may include back pain, headaches, numbness, dizziness, bowel/bladder incontinence, increased reflexes, incoordination and/or weakness or pain in the arms and legs.
In general, it is the pressure on the adjacent brain tissue or nearby nerves by the hemangioblastoma and/or associated cyst/syrinx that causes symptoms. Although treatment may be deferred even in the setting of a growing tumor, treatment should be initiated before symptoms become severe. The timing of intervention, therefore, is currently a delicate balance. Rarely can severe or longstanding symptoms/signs be reversed or diminished by tumor removal. Judicious surgical resection of tumors is critical because there is risk associated with surgical removal of hemangioblastomas of the brain or spinal cord, and asymptomatic tumors may never require removal. Thus, it is important to carefully consider both the benefits and risks.
When considering treatment options, always explore the three main choices: medication (chemotherapy, currently in experimental stage for VHL), radiation (primarily stereotactic radiosurgery for VHL), and surgery.
Stereotactic radiosurgery, sometimes called by the name of the machine such as gamma knife or cyberknife, is a non-invasive treatment which does not require open surgery. Radiation is delivered to a very specific internal area where the multiple beams of radiation meet and deliver a therapeutic dose. You should discuss stereotactic radiosurgery with your medical team, but it, like many other techniques, is not appropriate in every case, as it may cause post-treatment swelling or scarring that could make open surgery more difficult in the future. Stereotactic radiosurgery for any brain or spinal hemangioblastoma needs to be discussed carefully with a neurosurgeon knowledgeable about VHL.
The goal of all open surgical treatments is the complete resection (removal) of the hemangioblastoma. New surgical techniques and new surgical tools are being developed constantly, often to allow minimally invasive surgery. Regardless of the surgical technique that is used, the timing of surgery remains the most critical decision to make. No approach is always the right one. It depends on the particular tumor, its location and size, the associated risks of each approach, and the general condition of the patient. It is important that options are thoroughly understood, and the patient works with their medical team to arrive at the right choice. Do not hesitate to ask for second opinions. VHL or not, hemangioblastomas are rare tumors and few surgeons have a great deal of experience with them. It is helpful both to you and to your neurosurgeon to have multiple opinions on the best approach to your problem.
Special Imaging Considerations for the Brain and Spinal Cord
T1-weighted contrast-enhanced MRI remains the imaging modality of choice for determining the extent of nervous system hemangioblastomas and monitoring their growth over time. If possible, obtaining these with what radiologists refer to as a “3-D protocol” ensures that the image will be able to be compared to images from different centers with different imaging resolution and clarity. Contrast-enhanced MRIs are also recommended if symptoms or neurological signs develop. It can be difficult or impossible to accurately assess the extent and progression of hemangioblastomas using non-contrast enhanced MRIs. T-2 weighted and FLAIR MRI sequences are useful for determining the extent of swelling or cysts around a tumor as well as monitoring their progression over time.
Considering Stereotactic Radiosurgery
Stereotactic radiosurgery (SRS) is a non-invasive surgical technique similar to laser surgery, but using beams of radiation instead of light. As with all other forms of radiation treatment, the tumor or lesion is not removed, but the DNA is damaged. In addition, radiosurgery can also cause direct blood vessel damage, especially in vascular tumors such as hemangioblastomas, thickening and closing off of the blood vessels over a period of a few months, up to two years. Therefore, stereotactic radiosurgery is not effective “instantaneously’ like surgery. Though the beneficial effects may be delayed, initial side effects may occur and include swelling of the treated lesion due to the loss of the cells’ ability to regulate fluids as well as swelling in the brain tissue that is adjacent to the treated tumor.
There are three basic types of stereotactic radiosurgery: particle beam (proton—only at a few research locations), cobalt-60 (photon—Gamma Knife®), and linear accelerator (linac—CyberKnife®, Novalis Tx®).
After over 20 years of experience with SRS and hemangioblastoma, the VHL Alliance’s Clinical Advisory Council recommends:
SRS not be used for hemangioblastomas of the brain unless the tumor has been deemed unresectable by a surgeon with experience in VHL or if the patient is in very poor health and could not sustain open surgery
SRS not be used at all if the tumor is larger than 3 cubic centimeters (about 1.7 cm measured diagonally) or where a cyst is present, or when the patient is experiencing symptoms
SRS not be used at all in the spinal cord or CNS tissues other than brain, since it is still experimental with insufficient data on effectiveness or possible complications
The best candidate tumor for SRS is a brain tumor less than 1.7 cm in size which does not have an associated cyst and is not causing symptoms. Patients who have symptoms or cysts usually need to have standard surgical resection.
Because SRS works best with small tumors, some of the tumors chosen for treatment might, in fact, never have grown. Most doctors prefer to wait until the tumor shows some signs of enlarging but without development of a cyst before considering treatment with SRS. The long-term effects of SRS are not yet known, but doctors have seen scarring following SRS treatment that may make some subsequent surgeries more difficult.
The following list of questions has been assembled to help you engage in a discussion with your doctors to see if using SRS in your particular situation is the best choice.
(1) Get opinions on both surgical techniques. Consult with physicians about BOTH conventional micro-neurosurgery AND stereotactic radiosurgery. It is NOT enough to speak only with a radiation oncologist, interventional radiologist, or someone who practices only SRS. Be sure to talk with surgeons who are experts in each method and get both perspectives. In many cases, it is safer to approach a tumor with conventional surgery. If it is removed, the tissue can be examined under a microscope and the recovery period is better defined. Of course, conventional surgery has its own set of risks and drawbacks. It is important to assemble a team of medical professionals who can help fairly evaluate the pros and cons of both procedures and decide which is better for you in this particular situation at this particular time.
(2) How big is the tumor? Recommendations are NOT to treat a hemangioblastoma larger than 1.7 cm. Size is not the only issue, but it is a very important issue. Dr. Haring Nauta of the University of Louisville Hospital states, “It is a matter of how finely you can focus the beams of radiation. It is rather like trying to burn a hole with a magnifying glass and sunlight. To make a small hole, you can focus the beam to a small point and use less radiation. To make a bigger hole, you have to cover a larger field; the beam is more weakly concentrated, and you have to use a lot more radiation to do the job. The tumor absorbs more energy and will swell more after the treatment.”
(3) Is there a cyst or other source of mass effect? Mass effect is the effect of having some additional mass in your skull. This could be from a cyst, swelling, or from the tumor itself. If there already is extra pressure inside your skull, SRS is probably not a good idea since the additional swelling caused by the procedure would compound the mass effect and make the symptoms worse.
(4) Where is it? Once treated, there will be swelling (edema) of the tumor and surrounding tissues. What this means to you is that the treated tumor may get bigger before it gets smaller. Depending on how much room there is for it to expand, your symptoms may get worse before they get better. Where is the tumor located? When it swells, what symptoms may occur? How will the doctor propose to control the swelling? How can you work in partnership with the medical team to minimize the swelling and get through the swelling period? Note that this period of swelling is not measurable in days, but in months. Ask your doctor how long you should expect this swelling period to last.
(5) What are the dangers to surrounding tissues? There is usually some margin of healthy tissue that will be irradiated with a therapeutic dosage. What tissue is within that margin? What would such damage do? If the tumor is in a position where there is fluid beside it, then there is some “margin for error,” but if it is in a critical spot, then its effect on the nearby healthy tissue can be significant.
(6) How many tumors do they propose to treat? What is the sum of the radiation to which you would be subjected? If more than one tumor is to be treated, is it wise to treat them all at this same time or is it better to treat them one at a time? Pacing the treatment can be critical to managing the post-treatment swelling.
(7) What experience does this team have with treating hemangioblastomas, as opposed to solid tumors? Hemangioblastomas react differently to radiation treatment. It is important to get someone with experience in treating hemangioblastomas to participate in reviewing the treatment plan prior to the beginning of treatment. If you cannot find someone in your area, the VHL Alliance can suggest some sources for second opinions. This should be welcomed by your team as it is for their protection as much as for your own.
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