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Gamma Knife Radiosurgery: The Most Advanced Technology of its Kind on the Market.

Roswell Park Comprehensive Cancer Center is now treating patients with a brand-new, state-of-the-art Gamma Knife radiosurgery device, the Leksell Gamma Knife® Icon™ — the most advanced technology of its kind on the market. Roswell Park Comprehensive Cancer Center is the first cancer center in the United States to receive a license to operate it and remains the only facility in Western New York with Gamma Knife capabilities. We have used Gamma Knife radiosurgery to treat patients with brain tumors and metastases for 18 years. This latest technology comes with certain advances that mean more patients may qualify as candidates for the treatment, and the ultra-high accuracy minimizes long-term side effects, improving outcomes.

In this segment, Dheerendra Prasad, MD, MCh, FACRO, Medical Director, Department of Radiation Medicine at Roswell Park Comprehensive Cancer Center, discusses the brand-new, state-of-the-art Gamma Knife radiosurgery, the most advanced technology of its kind on the market.

Gamma Knife Radiosurgery: The Most Advanced Technology of its Kind on the Market.
Featured Speaker:
Dheerendra Prasad, MD, MCh, FACRO
Dheerendra Prasad, MD, is the Director of the Gamma Knife Center at Roswell Park Comprehensive Cancer Center.


Transcription:
Gamma Knife Radiosurgery: The Most Advanced Technology of its Kind on the Market.

Bill Klaproth (Host): Roswell Park Comprehensive Cancer Center has treated more than 9,000 patients with Gamma Knife Radiosurgery. So what is it and how is it used in the fight against cancer? Here to tell us more is Dr. Dheerendra Prasad, MD, MCh, FACRO, Director of Roswell Park Comprehensive Cancer Center’s Gamma Knife Center. Dr. Prasad thank you so much for your time. Can you first explain to us what is Gamma Knife Radiosurgery?

Dr. Dheerendra Prasad (Guest): Yes, Bill, Gamma Knife Radiosurgery is a very high precision technique of performing treatments on tumors inside the brain using focused gamma rays. So in fact it is radiation that is pinpointed to a target inside the brain. It has the accuracy of one third of a millimeter and it basically will destroy or vaporize a tumor that is targeted with this technique.

Bill: So the tool is surgical but there is no cutting, no incision, right?

Dr. Prasad: That’s correct. The word surgery in gamma knife is retained mostly to imply the very high level of precision. It was a tool developed by a neurosurgeon in Sweden, but the energy it uses is actually radiation. It’s radiation coming from cobalt 60, which is gamma rays, hence the name gamma knife. So in reality it allows a neurosurgeon, radiation oncologist, and a medical physicist together to perform surgery on the brain without ever actually having to make an incision.

Bill: That’s amazing. Now is there anesthesia? Is the patient awake during this procedure?

Dr. Prasad: The patient is awake during this procedure. Patients do not feel any pain or discomfort during the procedure. In order to achieve the high precision of this technique we do fix to the patient’s head what is called a stereotactic frame. When the frame is applied to the patient’s head we do require some sedation and of course we use local anesthetic. But that happens at the very early part of the procedure, pretty much in the first half hour. And after that the patient experiences absolutely no discomfort or pain.

Bill: So who is a good candidate then for the Gamma Knife Radiosurgery?

Dr. Prasad: Patients who have developed tumors in the brain as a part of their cancer, so called metastatic tumors or secondary tumors, are the prime candidates for the gamma knife in a cancer setting. Of course we also treat with the gamma knife tumors that are not cancerous, but are present in and around the brain. And so we treat of course metastatic cancers coming from lung, breast, colon, kidney cancer, and melanoma, whenever these end up involving the brain these patients become candidates for Gamma Knife Radiosurgery. But there are also patients who develop other conditions, such as tumors of the hearing nerve called acoustic neuromas or benign tumors of the lining of the brain called meningiomas, which in fact are quite common. In those patients this offers a nonsurgical or minimally invasive approach to dealing with their problems. And believe it or not in addition to tumors we also treat conditions such as nerve pain, called trigeminal neuralgia, and movement disorders, like essential tremors, something like Parkinson’s disease, except the disease more of the elderly in which there is uncontrollable tremor. So at the Gamma Knife Center at Roswell Park since we are primarily a cancer center the vast majority of patients we treat have malignant tumors in the brain, but there is also a large number of patients we treat with other conditions since we have the technology.

Bill: So there are many uses for the gamma knife treatment. Now is it only used on the brain or do you use it on other parts of the body?

Dr. Prasad: As I said, Bill, earlier the technique was developed by a neurosurgeon and of course its primary focus was the brain and he was swimming against the tide of the way radiation was used in the day. Clearly this technique allows the entire treatment to be delivered in one day, which is very different from most people’s experience with radiation treatments, which take several weeks to months. But in so doing he created the new paradigm for delivery, which over time has now been extended to other parts of the body. The gamma knife itself, however, remains a brain dedicated tool. We are able to treat the brain, the base of the skull, and the upper part of the cervical spine. But for everything else we use other tools that will produce very similar beams, and those tools are called linear accelerators. And those are used to treat other parts of the body.

Bill: So this is administered in one day you were just mentioning to us. It’s not like traditionally chemotherapy. So does the patient go home that day and resume normal activities?

Dr. Prasad: Yes, patients are able to return home the same day. Of course they have received a little bit of sedation and they have received a treatment. Most patients will feel somewhat fatigued at the end of the procedure so we recommend that they take a period of rest usually 24 hours and then they can resume normal activities.

Bill: So the recovery time is extremely short?

Dr. Prasad: That’s correct.

Bill: And does gamma knife technology help with recurrent tumors as well?

Dr. Prasad: Yes, it does. Because the technique is very highly focused and very precise it is possible to essentially contain all the radiation that is being delivered to the targeted cells. This defers from most any other way of delivering radiotherapy, which means even if we have treated someone before and we retreat the area, since all the dose will be contained on abnormal targeted tissue and normal tissue will receive very little additional dose, recurrent tumors become very suitable targets for this technique.

Bill: So this really does improve outcomes and quality of life for your patients?

Dr. Prasad: It has changed the thinking that we have about managing these patients. In the past not so long ago the moment patients develop metastatic tumors in the brain from lung cancer, breast cancer, or melanoma, or what have you, they were immediately subjected to a form of radiotherapy where the entire brain was treated with radiotherapy called whole brain radiotherapy. Now clearly large parts of the brain were not involved in tumor but it was the only technique available to treat these tumors in the brain. The advent of gamma radiosurgery, which has been around now for almost six decades, and it is increasing application to patients with cancer has shown that you can pinpoint and pick off only target tumor tissue in the brain leaving the rest of the brain completely unaffected by radiation. That provides not only a much quicker resolution for the problem for the patient, it also protects normal brain allowing for a much higher quality of life for the patient, a much higher level of cognitive preservation allowing their memory and their function to be preserved, and certainly has the added cosmetic advantage of not causing any hair loss.

Bill: Which is amazing, all of those benefits you just mentioned. Now Gamma Knife Radiosurgery has been around for a while, are their new advancements in gamma knife technology that we should know about?

Dr. Prasad: Yes, the gamma knife has been around for sixty years but it has been a steadily evolving technique. At Roswell Park we’ve actually always remained at the cutting edge of this technology. I have personally been involved with the gamma knife from 1992 and have treated more than 12,000 patients in my career. I have had the privilege of being able to stay abreast and keep the latest gamma knife technology available to patients at Roswell. We were in fact that first NCI designated cancer center in the United States to bring gamma knife icon to the United States. Which is the latest version of the gamma knife. The icon in addition to the traditional gamma knife technique that I just described to you, where we fix a frame to the patient and perform the treatment in entirely one session, allows an alternative way to immobilize the patient using a soft plastic heat molded mask so that the patients in whom we could benefit splitting the treatment into two or three or even five sessions in order to accommodate for location, proximity to critical structures, or size of the target, we are now able to do so. Clearly these patients in the past would have required repeated frame placements, which despite being a procedure we are very comfortable offering, still is somewhat inconvenient for the patient if done repeatedly. So the mask allows us to treat these special patients over several days. This is a new development in the gamma knife world. It is clearly very new internationally and we have been able to bring it here almost within the first 12 months of its inception anywhere in the world. And we were the first ones in the United States to deploy it.

Bill: So Roswell Park Cancer Institute is one of the first institutions to be able to offer the new gamma icon radiosurgery.

Dr. Prasad: That is correct.

Bill: Dr. Prasad thank you so much for your time today talking about gamma knife radiosurgery. For more information, visit RoswellPark.org. You’re listening to Cancer Talk with Roswell Park Comprehensive Cancer Center. I’m Bill Klaproth, thanks for listening.