Gamma Knife Center of the Pacific

Treatment of Brain Tumors
with Dr. Nicholson
From AmericasDoctors.com, March 7, 2001

Moderator: Welcome to this afternoon's AmericasDoctor Expert Chat with Dr. Maurice Nicholson on Treatment of Brain Tumor with Gamma Knife.

Moderator: Dr. Nicholson is currently Medical Director at the Gamma Knife Center of the Pacific, located at St. Francis Medical Center. He earned his medical degree from the University of Alberta School of Medicine, and completed his residency at Henry Ford Hospital in Detroit, Michigan. In addition to being a member of several professional organizations, including the Hawaii State Medical Society, American Medical Association and Hawaii Neurological Association, Dr. Nicholson was also appointed to the Editorial Board of the International Journal of Angiology. Dr. Nicholson is certified by the American Board of Forensic Medicine and is licensed in Hawaii and California. To contact Dr. Nicholson’s office call (808) 537 9595 or email neuronet@lava.net. For further information visit www.gammaknifehawaii.com.

Moderator: AmericasDoctor proudly presents Dr. Maurice Nicholson.

Dr. Nicholson: Welcome to today's chat. We are going to discuss the treatment of various types of brain tumors utilizing the gamma knife. The gamma knife is not a knife - it is an extremely accurate medical device that can treat most brain tumors with no incision and no hospitalization. I am happy to answer any questions.

Guest: My husband was diagnosed with a tumor on the front temporal lope of the brain, the doctors have recommended not to do the biopsy and just to do the surgery and take it out to stop the seizures. But, the want to induce a seizure first to make sure what kind it is, and numb the brain to check the speech and do another MRI just like to know your opinion on this?

Dr. Nicholson: It sounds like you are in good hands and they are doing the appropriate procedures. Whether gamma knife will be of use eventually can only be determined after they know the exact tumor and whether they will be able to completely remove it or not.

Guest: What's a gamma knife? Is it dangerous?

Dr. Nicholson: The gamma knife is a medical device that contains 201 sources of radioactive cobalt that are focused to a very small point. The gamma knife then does a precise and complete destruction of a chosen target without significant concomitant or late radiation damage to adjacent tissues. It is a very safe technique.

Guest: My father was diagnosed with a glioblastoma stage 4, brain tumor in August. He had surgery, chemotherapy and radiation. He has just completed surgery again at Wake Forest where the BCNU wafers were put in. In 4-6 weeks he will return to Wake Forest for a scan to see what has grown again. At this time, they will talk about the gamma knife. My question - what do we need to be looking for to catch the tumor small enough to do the gamma knife? And what is this size?

Dr. Nicholson: The treatment of glioblastomas is very difficult - external beam radiation is usually given but often a gamma knife boost is used. In your area, there is a Dr. Edward Shaw who is the Chairman of Radiation Oncology at Wake Forest University School of Medicine. He has extensive experience in the gamma knife. You may want to contact him or have your doctor contact him.

Guest: What is this used for? I have epilepsy - will it help this?

Dr. Nicholson: There are some very specific types of epilepsy that can be treated with a gamma knife. Most epilepsy cannot be. You would have to consult with a neurosurgeon experienced in this area to obtain a definitive decision.

Guest: My father was diagnosed with GBM IV. He had surgery and went straight on chemo. He did this for 3 months and then went back to the hospital because he couldn't speak. His doctor seems to believe the tumor is coming back. He will start radiation Monday for 6 weeks. If the tumor were still there would the gamma knife be an option?

Dr. Nicholson: The gamma knife might possibly be used as a boost. But, this can only be determined by the treating neurosurgeon and radiation oncologist. Their decision will be based on the MRI scan. It is not unusual for these tumors to recur.

Guest: Is more than one treatment needed?

Dr. Nicholson: Usually the gamma knife treatment is done once. Boost means that they will possibly use external beam radiation and they are limited by the dosage that they can give so a gamma knife can be used to put a more powerful dose into a smaller area without damaging the surrounding brain.

Guest: Could it be used on a mixed glioma III in frontal lobe that Drs. don't want to do surgery on right now? My wife had radiation and size is about 4 cm and is ill-defined.

Dr. Nicholson: This does not sound like a good lesion to be treated solely with gamma knife at this time. Usually, the gamma knife does not treat above 4 cm. If the margins are ill defined, the gamma knife is usually not the treatment of choice. Usually surgery and external radiation, sometimes chemotherapy and occasionally gamma knife for residual tumor after surgery.

Guest: Are there any long-term side effects from this procedure?

Dr. Nicholson: Usually, no. The complications and side effects are very uncommon. Occasionally, some brain edema or swelling can occur as a delayed response. This almost always responds well to medication.

Guest: Could you describe the basic physics involved with the gamma knife instrument?

Dr. Nicholson: The gamma knife destroys the ability of cells to multiply by breaking the DNA chain. It also causes neovascular intimal proliferation so the blood supply to the tumor closes off.

Guest: I've seen a kind of brace that goes around the head for this surgery - what is it and what else do you use on a patient?

Dr. Nicholson: It is not a brace - it is a Leksel Head Frame. This is a 4-pin attachment to the outside of the skull. It is applied with the use of a local anesthetic. This is to prevent head movement. That is, when the patient is in the MRI and when they are in the gamma knife, there cannot be any head movement during treatment because this is a very precise high dose of radiation. Patients do not find the head frame uncomfortable after it has been on a few minutes. It is removed immediately following the procedure.

Guest: My mom has GBM. She recently had a total resection of the tumor. The tumor was about 4 cm. She has been receiving radiation therapy for the past 5 weeks. She is planning on having a Gamma Knife procedure next week. Could you please tell me whether it is wise to go through with the procedure and if so what are the benefits and consequences?

Dr. Nicholson: The decision of whether or not to go through with this is between the family and the treating doctor. However, statistically, the recent literature has shown that survival time is almost double in patients who receive gamma knife boost after external beam radiation. GBM is an abbreviation for glioblastoma multiforme, which is a malignant brain tumor.

Guest: How many physicians are involved in the surgery?

Dr. Nicholson: The gamma knife team consists of a neurosurgeon, a radiation oncologist, a neuroradiologist, a physicist, and a nurse.

Guest: Doctor, would I be awake for this? It sounds painful.

Dr. Nicholson: Yes, you would be awake. There is no pain with this procedure other than momentary local anesthetic when the head frame is applied. You do not feel the gamma knife treatment. It is like having an x-ray treatment. Many patients fall asleep during treatment.

Guest: I have heard that on some tumors, after the gamma knife treatment is used, the tumor size has been reduced to "pea" size. Is this true, and if so, how long before the GBM IV tumor grows back?

Dr. Nicholson: GBMs are very malignant. Cures are very rare. The recent literature has shown increased survival with gamma knife boost. The prognosis is poor but overall, it is much better these days than even ten years ago. A definite time of tumor recurrence cannot be given. It varies greatly depending on the malignancy of the cells.

Guest: Where is it available?

Dr. Nicholson: There are about 40 places in the United States. If you can tell us where you live, I can possibly help you a little bit.

Guest: Sorry, doctor. I also meant to tell you that I live in California.

Dr. Nicholson: There is a gamma knife at UCSF. There is one in Sacramento, San Diego, at Good Samaritan Hospital in Orange County.

Guest: Is the gamma knife a first prototype for a range of future radiation instruments, or is it one of a kind?

Dr. Nicholson: The gamma knife is perhaps a prototype for future radiation instruments. It is used specifically for the brain but the concept is trying to be used for other areas of the body. There are some technical problems that need to be resolved. Research is being done. Gamma knife, per se, will not be used for any other area, just the brain. They are working on a similar type of instrument to treat other areas.

Guest: I have been treated with Stereotactic Radiosurgery in Australia for an acoustic neuroma

Dr. Nicholson: Since there is no gamma knife available in Australia, you were treated on a linear accelerator. This can be used if a gamma knife is not available, however, it is not as accurate as the gamma knife and the complication rate is higher. We are trying to establish a referral system from Australia to Hawaii. We have been corresponding with various people in Australia and New Zealand trying to establish a referral system to our Gamma Knife Center in Hawaii. Indeed, we have corresponded with the Minister of Health in New Zealand who has expressed some interest. You would have to have your doctor there, refer you to a neurosurgeon there, then have them refer to our Gamma Knife Center and then have authorization from your insurance company, or be willing to pay out of your own pocket. A linear accelerator is the standard machine used for radiation therapy. They put a modification on it to do a stereotactic surgery and then take the modification off to do regular radiation therapy. This is unlike the gamma knife, which does nothing but stereotactic surgery.

Guest: How long will it take me to recover from this treatment?

Dr. Nicholson: People go back to work the day afterwards, or go shopping, depending. That is depending on whether you work or not.

Guest: How come the gamma knife cannot destroy the whole GBM tumor? Does the radiation penetrate the blood-brain barrier?

Dr. Nicholson: The problem with GBM is that you cannot see the exact margins of the tumor. The reason it recurs so frequently is that there are often cells a long way from where the tumor appears to be.

Guest: The treatment of acoustic neuroma by this method is quite controversial in Australia.

Dr. Nicholson: Perhaps it is controversial because there is no gamma knife in Australia. It is not controversial in most of the world. The recent literature has shown a 98 percent tumor control. Neurosurgeons in Australia like to operate on acoustic neuromas which is to be expected as that is what they are trained to do. If there is a choice between a linear accelerator and surgery, perhaps surgery is better. However, the results of the gamma knife are obvious if you read the literature. Certainly, the risk of facial paralysis and other complications is much, much lower using the gamma knife.

Guest: Would a follow-up treatment of chemotherapy be advisable after Gamma Knife?

Dr. Nicholson: Perhaps. That would have to be determined by the clinical course and the MRI findings.

Guest: How many Gamma Knife procedures have been done at your center?

Dr. Nicholson: In the past two years, we have performed approximately 200 procedures. We have done a series of approximately 30 acoustic neuromas. We have done approximately 40 metastatic tumor patients and multiple various other types of tumors.

Guest: What conditions determine if you are a candidate for the gamma knife (i.e., tumor size, type of tumor...)

Dr. Nicholson: You are correct, tumor size is important; it must be under 4 cm. The type of tumor is also important. The age and condition of the patient is important and sometimes, patient preference.

Guest: Do most U.S. insurances cover this?

Dr. Nicholson: Yes. Medicare and other insurance programs will cover it.

Guest: How many doctors statewide are trained to use the Gamma Knife?

Dr. Nicholson: There are 9 neurosurgeons and 5 radiation oncologists.

Guest: What sets Gamma Knife apart from other breakthrough brain treatments & procedures?

Dr. Nicholson: The gamma knife is unique because it is basically an outpatient procedure. It has very few complications.

Guest: I've heard the term AVM used before. What is it?

Dr. Nicholson: AVM is arteriovenous malformation, which is an abnormality in the blood vessel. AVMs are treated with the gamma knife. The danger of AVMs is that they bleed and cause paralysis and/or death. They can also cause seizures. For more information on AVM’s, we are going to have a discussion regarding AVM with Dr. Liem on Friday, March 23 from 2 p.m. to 3 p.m. HT. His chat title will be Vascular Malformations and Gamma Knife. It is also sponsored by St. Frances Healthcare System of Hawaii and the Gamma Knife Center of the Pacific.

Guest: My cousin is too large to fit in an MRI - would the MRI at St. Francis accommodate a 300-pound person?

Dr. Nicholson: Yes, this is a problem with some gamma knife centers in as much as the MRI scanner does not accommodate large people. One of our first treatments was from Oregon and he could not be treated on the mainland and he came to Hawaii to our center.

Guest: What is a metastatic tumor?

Dr. Nicholson: It is a tumor that has spread from another area of the body such as breast cancer, colon, kidney, etc. Yes, there has been an evolution in treating metastatic brain tumors. The changes being from whole brain radiation, which was the standard a few years ago, to using at the present time, the gamma knife to treat each individual metastases and not do whole brain radiation until, if ever, at a later date. The results are better and the morbidity to the patient is less using a gamma knife. Also, a recent large study has shown the recurrence rate after treatment to be higher when the linear accelerator is used as opposed to the gamma knife.

Guest: Could I send MRI films and notes for a free "review" by your medical team?

Dr. Nicholson: Yes, we frequently do this. The final decision depends on the patient and the doctor. We can give advice and recommendations.

Guest: If a tumor recurs after radiation treatment, can the procedure be repeated?

Dr. Nicholson: On rare occasions, a second treatment is used. This is for malignant tumors. Benign tumors do not require a second treatment.

Guest: Are there Gamma Knife centers in the state of Iowa?

Dr. Nicholson: There is a site in Cleveland at the Cleveland Clinic, Chicago Institute at Columbus Hospital, and Northwestern University Medical School in Chicago also has one. If you would like to make a trip to Hawaii, we'd love to see you!!

Guest: Why is radioactive cobalt often used as a source of gamma rays? Are there different wavelengths within the gamma ray frequency spectrum?

Dr. Nicholson: The gamma knife has always used radioactive cobalt. No other sources have been used.

Guest: If all the conditions of a GBM are right (size, good patient health, etc.), can the gamma knife be used on this type of tumor?

Dr. Nicholson: I think that, at the present time, we would still recommend external beam with a gamma knife boost.

Guest: Can the Gamma Knife be used more than once on the same tumor in the same location?

Dr. Nicholson: It can be if necessary. It is very unusual to have to do this. People with metastatic tumors can be treated on more than one occasion if new metastases appear later (appear later after being treated).

Guest: My father was told they have the gamma knife in Davenport Iowa. Are you aware of this one?

Dr. Nicholson: I do not know, but there certainly could be one there. Our records may not be up to date.

Guest: Is there a difference between Gamma Knife and Gamma knife boost?

Dr. Nicholson: There really is not, we just say boost when used in conjunction with external beam.

Moderator: Dr. Nicholson will now give his closing statement.

Dr. Nicholson: Thank you joining me this afternoon on our discussion of the gamma knife. This has been a very interesting hour with excellent questions. We would be very happy to answer any questions that are forwarded to the Gamma Knife Center. If anyone would like to travel to Hawaii for treatment, we would be happy to take care of you. Our number is (808) 547-6865 if you would like to speak to me further about this or contact our Center in Hawaii.

Moderator: This brings tonight's chat to a close. Again, if you would like to contact Dr. Maurice Nicholson or the Gamma Knife Center in Hawaii, please call 808-547-6865. Also, please be sure to check back on the AmericasDoctor web site for upcoming Expert Chats on other topics of chronic illness and Gamma Knife Surgery. Our communities, library, and message boards are also available to you on www.AmericasDoctor.com. Thank you and good night!

Moderator: Dr. Nicholson is currently Medical Director at the Gamma Knife Center of the Pacific, located at St. Francis Medical Center. He earned his medical degree from the University of Alberta School of Medicine, and completed his residency at Henry Ford Hospital in Detroit, Michigan. In addition to being a member of several professional organizations, including the Hawaii State Medical Society, American Medical Association and Hawaii Neurological Association, Dr. Nicholson was also appointed to the Editorial Board of the International Journal of Angiology. Dr. Nicholson is certified by the American Board of Forensic Medicine and is licensed in Hawaii and California. To contact Dr. Nicholson’s office call (808) 537 9595 or email mailto:neuronet@lava.net. For further information visit www.gammaknifehawaii.com.

Reviewed by Steven J. Adashek, MD, FACOG, March 7, 2001